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The Lockback KnifeFrom Design to Completion

Peter Frontedduand Stefan Steigerwald

4880 LowerValley Road,Alglen. Pennsylvania 1 9 3 1 0


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Other Schif fer Books o n Related Subjects:Basic Knife Making: From Ftaw Steel to a Finished StubTang Knife 978-0-7643-3508-2 - $29.99Translated from the Germn by Christine Ell iston.Original ly published as Back-Lock-Messer: Von derKonstruktion zum fertigen Klappmesser by Wieland Verlag.Copyright '& 2010 by Schiffer Publishing Ltd.Library of Congress Control Number: 2009943047

All rights reserved. No part of this work may bereproduced or used n any form or by any meansgraphic,electronic, or mechanical, including photocopying orInformation storage and retrieval systemswithout writtenpermission from the publisher.The scanning, uploading and distribution of this bookor any part thereof via the Internet or via any other meanswithout the permission of the publ isher s Ilegal andpunishable by law. Please purchase only authorized editionsand do not part ic pate in or encourage the electronic pracyo f copyrighted materials."Schiffer," "Sch i f fe r Publishing Ltd. & Design," and the"Design of pen and inkwell" are registered trademarks ofSchif fer Publishing Ltd.Designed by Stephanie DaughertyType set in Dutch809 BT/Zurich BTISBN:978-0-7643-3509-9Printed n China

Schi f fer Books are available at special discounts fo r bupurchases for sales promotions or premiums. Speceditions, including personalized covers, corporate imprinand excerpts can be created in la rge quantities fo r specneeds. For more information contact the publisher:Schif fer Publishing Ltd.4880 Lower Valley RoadAtglen, PA 19310Phone: (610) 593-1777Fax: (610) 593-2002E- m a l : [email protected]

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ContentsA Few Introductory Sentenc es 4

1. Intial Thoughts 51.1 Gen eral Co nsiderat ions 51.2 T h e K n i f e 51.3 Mater ia l Selection 6

2. Design, Sketch, and a Functional Tmplate 92 .1 De s ign Fun da m e n t is 92 .2 Concre te Design Elements 92.3 Creat ing a Funcl ional Tmp la te 10

3. Producing the Liners 214. Making the Blade 315. The Locking Mechanism 426. The Blade Lock 587. Making the Spacer 608. Grinding the Blade 669. Making th e Bolsters 71

10 . The Blade Pivot 8311. Customizing the Handle 8912. Making the Washers 9913. Design Variations 10214. Finishing and Final Steps 110


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A Few Introductory SentencesCreating all kinds of folding knives is one of m y greatest interests. So many individual pawork togethcr and result in a func t ion ing system. T he fit, combination , and d esign of cach knalways prcsent a new ch al lenge. M any problems arse whi le making th e knives in this book , bwere resolved as easily as possible. With each issuc w e faced Pcter Fro n te d d u asked me hoand why I handlcd the problem the way I d i d m u c h has become natural for me. My approato the problems , which w e discuss in th is book, should not be considered absolute , bu t mathe lockback knife lock system comprehensible. This frees th e knifemaker from predetermindesigns and encourages exp erimentat ion. Is there an yth ing bet tcr?

Stefan Steigerwald

First and foremost , I would like to thank Stefan Steigerwald. It was pur luck that I was abto work with a bladcsmi th w i th vast technical knowledge who can realize h is design conceptsso m any ways. A s a non-b ladesmi th and observer, 1 hope th e text and pictu res allow th e readto see how the f u n d a m e n t i s of designing and construct ing a lockback knife became clearm e in the course of my collaboration with Stefan Steigerwald.M a n y t h ings are not as s imple as they seem wh en looking at a finished knife. In contrastindust r ia l manufacturng, when constructing individu al handmade pieces, imp rovisation; instinand; above all , patience are necessary. For me those are the in t r ins ic va l es of a completknife; for me, it is what makes a handmade knife appealing. The more I learn the more I cappreciate it .Therefore, I hope that this glim pse beh ind th e scenes of knife m a k i n g also interests thowho do not intend to p u rs u e th e hobby. And I encourage those who are insp i red to tackle yofirst project!

Peter Fronteddu


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1. Initial Thoughts1.1 General Considerations

There is not a s i n g l e p r o v e n m e t h o d fo r d e s i g n i n g and cons t ruc t ing a lockback knife .t h i s book we desc r ibe the p roduc t ion o f a pa r t i cu l a r knife, b u t also discuss a l te rna t ive desifea tu re s and p rodu c t ion m e thods . W e use concre t e examples t h r o u g h o u t t he processfrom tf i rs t ske tch to a c o m p l e t e d kn i fe .

W c will a lso d iscu ss the basic technica l q ual i t ies of a lockback kn i f e . These a re the con s t ant h a t are necessary for proper func t ion . T he specific w ay these technical aspects are executis left up to you, the k n i f e m a k e r . Our book i s not necessar i ly a manual for " the o n e " m e t h orather, w e w a n t to prov ide yo u with a t e c h n i c a l f o u n d a t i o n t h a t you can use to i m p l e m e n t yoow n ideas .T h i s approach inc ludes i n t r o d u c i n g v a r i o u s p r o d u c t io n m e t h o d s a n d kn i fe des igns , a galle

of w hi ch you wi l l f ind a t the end of th is guid e . No t eve ryone can or w ants to use ex tens iand expensive machincry . Thcrefore , in var ious scct ions we wi l l iden t i fy other solut ions ant e c h n i q u e s u s i n g s i m p l e m e a n s .W e m u s t i n c l ud e a brief note on work safe ty . Because we documented the i n d i v i d u a l stepho tograph ica l ly , necessary and pract ica l safe ty m easures w cre par t ly spared . An yone m a k i n gkni fe should become famil iar with the necessary m easures tha t guar antc c a safe work cnvi ronm eb e f o r e h a n d , espec ia l ly wh en power tools a re b e i n g us e d .

1.2 The KnifeBefore m a k i n g any i n i t i a l ske tches , w c s h o u l d d e f in e the bas ic componen t s of the kni

O ur e x a m p l e s h o u l d be a pocket- f r iendly kn i fe . There fore , w e def ine the l eng th of the b ladeapproxima te ly 90 m m . I t is also imp o r t an t t ha t no edges p ro t rude outwards on a comple tknife .T he const ruct ion should be screwed toge ther and n ot r ive ted . This h as v a r i o us a d v a n t a g eFirst , mi s t akes m a d e du r ing produ ct ion can be easily corrected s ince you can access and re -woth e i n d i v i d u a l pa r t s . Second , a knife that is screwed together is easier to clean. Finally, you cla ter replace i n d i v i d u a l pa r t s (washe rs , sp r ings , e t c ) .For the l ock ing device we have chosen two basic var ia t ions . The firs t stylc f ea ture s a dcv itha t extends fa r toward the back of the k n i f e and locks a t the en d of the h an dle . For the o th

var ia t ion , the lockb ack i s re leased tow ard th e m idd le o f the han d le . W e wi l l show bo th op t ionas well as diffe ren t v e r s i o n s for th e l o ck in g sp r ing .


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Initial Thoughts

Knife Anatomy Locking Mechanism PivotBlade Notch

Latch Locking Mechanism

Blade Pivot Washer Base of the Blad e Liner Spring Spacer

In the classic versin of a lockback locking mechanism, the locking mechanismextends over the entire lengthof the handle. There are also shorter versions.

1.3 Material SelectionT y p i c a l l y the f i r s t t h i n g to cons ide r when m a k i n g a kni fe i s the correc t type of s tee l to ufo r the b l a d e . For our pocketknife we a re p l a n n i n g to use a s tee l th a t i s ca sy to h a n d l e and ava i l ab l e i n the r e q u ir e d d i m e n s i o n s . In a d d i t i o n , the m a t e r i a l s h o u l d not be too costly to f i n i si l sho u ld be ea sy to g r i n d to a f i ne cu t t i ng edge , have s t rong edge re ten t ion (i.e. h a rd n e s s a nc a rb i d e d i s t r i b u t i o n ) , a n d b e ru s t- r e s i s t a n t . F u r t h c rmo re , t h e m a t e r i a l sh o u l d b e a f f o r d a b l c .Se lee t ing s tee l is a lway s a c omp rom ise . A su i t ab le ma ter i a l i s one tha t meets each r e qu i r e m ea s m u c h a s poss ib le . There fo re , our choice is RWL - 3 4 , th e p o w d e r - m c t a l lu r g i c a l v a r i a n tATS-34. For the d ec o r a t i ve ve r s i n of our kn i f e , however , w e have dec ided on an i n d u s t r i a lp ro d u c ed , p o w d e r - m e t a l l u r g i c a l D a m a s c u s steel wi th a f i ne v i sua l a p p e a r a n c e .Natura l l y , there a re man y op t ions when sc l c c t i ng s t eel . U n f o r t u n a t e l y , a d e t a i l ed d i s c u s s i oof steel is not in the scopc of t h i s g u i d e .We do, however , have s o me a d v i c e for m a k i n g th e p ro p e r d ec i s i n . T he q u e s t i o n of steelp r i m a r i l y a ques t ion of t a s te . Make you r dec i s in ba sed on p e r s o n a l p re fe rences , how you w

use the k n i fe , y o u r d ec o r a t ive i n t e r e s t s , o p t i o n s fo r t r e a t m e n t , a n d p r i ce . There i s no co r rec ti nco r rec t dec i s in .T he va r i e t y of steels a v a i l a b l e to the kn i femaker ha s i n c r e a sed c o n s i d e r a b ly in recent yearT here is now a r ange o f n o n - a l l o y a n d low al loy carbn s teels (1095, CK60, CK 75, 1.2842, ano t h e r s ) . T h ey form f ine c u t t i n g c d g c s , h a ve a h ig h h a r d c n a b i l i t y , an d a r e su f f i c i en t l y s t ab leth e c u t t i n g edge . Ca rbn s tee l s a re easy to h a n d l e , heat t rea t , a n d g r i n d a n d they a re r a t hi n exp en s i ve . Th e i r ma i n d i s a d va n t a g c i s t h a t t h ey a r e n o t r u s t - r e s i s t a n t ( i n f a c t , there i s rea ln o such th ing a s a r u s t p r o o f , h a r d en a b l e s t e e l) .

6


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Initial ThougFor the knifemaker who places v a l u on rus t - res i s t an t k n i v e s , h i g h alloy s teels containich r om i um , s uch as ATS-34, 440C, 154-CM, A U S- 8 , and 12C27 are avai lable . Normally tadvan t ag e of rust- resistance comes at the expense of hav ing a cu t t ing edge that is not as f ine acarbn steel blade. High alloy steels at the same hardn ess as a carbn steel tend to be less stabw h i c h , however , does not play a h u g e role with the d i m en s i o n s of our pocketknife b l a d e .Hig h alloy, ru st-resistan t steels that are p r oduce d in a powder-metal lurgical processo n e step fur ther . D u r i ng t h is m a n u f a c t u r i n g process m a n y smal l , cve n l y d i s t r i b u t e d ca r b idform. These carbides crate e las t ici ty and edge re tent ion that exceeds that of carbn steels convcnt ional c hrom ium s tee ls . In compar i son , the h igh alloy steels tha t are not produced wip ow de r meta l lu rgy form larger and u n e v e n l y d i s t r i b u t e d carbides . These cou ld break out in tcu t t ing edge and lead to microscopic n ick ing . This p h e n o m e n o n crales a f ine s aw t oo t h , w h iis well sui ted for a pul l ing cut if t ha t is w ha t you are looking for.An other mate r ia l to consider is Damascus s teel . Due to the revival of b l a d e s m i t h i n g in rcceyears , a large se lect ion of ha nd forged Damasc us s teels are now ava i lable . The Sw edish comp aDamastee l , fo r example , uses powder m eta l lu rgy to p r oduce a rus t - res i s t an t Damascus s tee lToday the use of Dam ascu s steel is more a question of aesthetics. Even with high qual i ty indus t rsteels, made by blend ing var ious types of steels, a perform ance edge can hardly be achieved. Awith hand forged Dam ascus s teels, wh ich are m a d e specifically to improve performance, a possibimprovement in qual i ty is incommensurate to price and effort. That is not fundamental ly an a r g um eagainst us ing Damascus s tee lindividual i ty cannot be measured , even with a price.W h a t is general ly miss ing from discuss ions regard ing stccl are the q ue s t i ons of hea t t r e a t m eand cu t t in g edge geometry . Like mater ia l se lec t ion , bo th charac te r i st i cs have the same effon cu t t ing perform anc e. Only wi th approp riate heat t reatme nt does th e steel obtain its desircharac te r i s ti cs hardness , flexibility, f ineness of the cu t t ing edge , and rust-resistance. A he

t rea tm ent th a t i s no t o p t imal e l imina tes the po ten t ia l ben e l i t s o the s t ee l. Therefore , only ua s t ee l fo r which you un ders tand the hea t t rea tm ent p rocess regard less of wh e the r you hardthe steel yourself or give th e steel to a heat t rea tment w o r k s h o p .Blade geomet ry has a deci s ive i n f l u e n c e on the c u t t i n g abili ty and r ob us t ne s s of the bladThe edge angle determ ines the forc needed for cut t ing i.e. th e smaller the edge anglc, th e sharpthe blade and the less pressu re y o u need to cu t with th e knife . On t h e other hand , th e cu t t iedge must correspond to the s teel and i ts usage. With high alloy steels there is the danger carbides breaking ou t with a cut t ing edge that is too fine.Con clusin: when select in g a s teel, only consider ing the type of s teel i s c u t t i n g the issshor t . Ins tead , in choosing your s teel , y ou must reach a compromise between s teel type , het r ea t m en t , a n d blade geometry.W e left th e he a t tr e a t m e n t of al l blades discussed in t h i s gu ide to a heat t rea tment workshthat has ex perience wi th knife blades and the types of steel we plan to u se. The results from thpar t i cu la r shop are advantageous because the blades are hardened in a v a c u u m fu rnacc , whisignificantly reduces th e a m o u n t of scale (an oxide layer) that w e will need to gr ind off. Befosending the blade to this shop for hardcning we can nearly com plete the finishing and satin-f inishprocess. W e find it sufficient to leave 0 .2 mm to 0 .4 mm on the cu t t ing edge before har den ing.


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nitiai ThoughtsW e w i l l comple te th e f rame of our k n i fe w i th 2 A1 V pur t i t a n i u m . Ti t a n ium i s l i gh t , v e rs table , complcte ly rus tproof , and changes color . T h e s p r i n g - t e m p e r e d t i t a n i u m 6 A 1 4 V is mordi f f icu l t to work wi th and does not offer any advan tag es for our pu rpo se . The l iners for the kni fare 2 .0 mm t h i c k . This gives the knife i t s des i red s tabi l i ty and provides enoug h m ater ia l for thth re ad th a t we have to cut i n to the l i n e rs .F or th e bolsters w e w i l l u se p o wde r me ta l l u rg i ca l RW L -3 4 stee l that , togcther wi th th e bla dis h arde n e d at 59-60 on the Ro ck we l l scale ( H R C ) . In a hardened s tate th e steel is less su sce p t i b

to scratches. For the decorative vers in we w il l make the bolsters from Damascus steel. Tlierare many opt ional mater ia l s for the bols ters ( i . e . mo kum e, brass , n icke l si lver , bronze , e tc .Ch o o se one th a t fits th e qual i ty and ap p e aran ce of the blade and the h an dl e scales.Like the bols ters , th e choice of m a t e r i a l for the handle scales is a m a t t e r of taste. For thd i f f e r e n t v e rs i o n s of our knife w e have chosen s tabi l ized w ood, moth er of p e ar l, b o n e , mam mo tivory, an d meteoric i ron. A s a basic principie th e handle mater ia l s hou ld correspond to the q u a l iof the kni fe . You should also pay at tent ion to the mat e r i a l ' s l o n g e v i t y so that the hard work yopu t i n to de v e l o p i n g accu ra te f i t t ings is not l o st . T h e re fo re , w i th w o o d w e suggest u s in g s tabi l iz

mate r i a l s or a very hard wood ( i .e . de se r t ironwood, grenadi l la , b o x wo o d , or e b o n y ) .T ake n o te , man y m ate r i a l s th a t a re often u se d fo r h a n d m a d e kni fe s h av e h i dde n h e a l th r i s kan d requi re extra p r e c a u t i o n s w h e n h a n d l e d . D u s t an d o th e r p ar t i cu l a t e mat t e r from m a ntropical woods and composi te mater ia l s are toxic or at least a l l e rge n i c .In p ar t i cu l a r , s t ab i l i ze d w o o ds c o n ta i n acry l i c re s i n s an d m o th e r o f p e arl co n ta i n s a rse n iAlso , carbn f ibers are respi rable . The use of su i table resp i rators and exhaust sys tems s s t ronglre co mmcn dcd . Re ta i le r s w h o offer k n i f e mak in g su p p l i e s sh o u l d b e able to h e l p w ith the se lect ioof su i ta b l e mate r i a l s an d an sw e r q u e s t i o n s o n p ro p e r h a n d l i n g .For our loc k ing m e c h a n i s m w e w i l l use R W L - 3 4 or 1.4034, e a ch b r o u g h t to b l ade h ardn e sFor the i n se r t e d sp r i n gs w e w i l l u se spring s tee l 1.4310 ( r u s t p r o o f s p r i n g s t e e l s t r i p ) wi th

40-45 H R C hardness . Al ternat ive ly , sp r in g s t e e l s mad e of carbn steel are also avai lable. Thesare not rus tproof and th e re fo re h av e a h i gh e r h ardcn ab i l ity , w h i ch cau se s m o re stress in thmateria l . Knife ma king su ppl y s tores should carry su i tab le rou nd or f a t stock. In the ba ck of thg u i d e y o u w i l l se e an o th e r v e rs i n of the lockback kni fe , for w h i c h w e co n s t ru e te d th e l o c k i nm e c h a n i s m and spring from a s i n g l e component, the rus t-res i s tant 1.4034 s tee l , hardened ant e mp e re d at ap p ro x i mate l y 45 H R C .

Fo r sc re wi n g to ge th e r th e pars of a knife , high-grade s tee l i s r e c o m m e n d e d , preferably oV 2A or V4A qual i ty . W e wil l use TX6 torx cyl inder head screws. T he heads are part ia l ly s t r ipefor a s l im visual appearance . For our knive s the outer diameter of the heads i s s ized 3 .8 mm t3 .0 mm. Part of the screws s h o u l d b e go ld -p la t ed you have to spoil yourself some t i me s .

T h e b l ade p i v o t s are m a d e from t i t a n i u m , p r i m a r i l y fo r v i su a l reasons . Al ternat ive ly , you cma ke pivots out of brass or steel . Brass has good anti-friction prope rties, is eas i ly o b ta i n ab lan d e asy to wo rk w i th . W e s h o u l d p o i n t o u t th a t y o u r pi v ot m ate r i a l m u s t b e ap p ro x i mate lfive t o t en H RC de gre e s softer t h a n th e b l ade . Be cau se l i t t l e p r e s s u r e i s placed on the b l a dpivot in the ro tat ional d i rc ct ion , the qu est ion reg arding mater ia l for the blade p ivots i s rat hcn o n -cr i ti ca l . Smo o th b l ade ac t i o n , how ever , i s e sse n t i a l .


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2. Design, Sketch, and a Functional Tmplate2.1 Design Fundamentis

A pocketknife should be made fo r daily use. It should be small enough to fit in your pocketlarge enough to take care of everyday tasks. A blade length of around 90 m m is a good compromDepending on the dcsign, a finished knife should have an effective cuttin g length of approx imatelymm. Wewill later grind the entire width to achieve an optimal cutting angle at the cutting edge2.2 Concrete Design Elem ents

Th e basis of our design is the classic lockback var iat ion. The locking mechan ism for this knis operated at the end of the handle. We will add bolsters to the handle to protect the hanscales underneath, visually exten d the blade , and give the knife a h igh -qua l i ty look. Alte rnat ivescales can be added over the ent i re length of the handle .To be able to adjus t the blade play in the completed knife , the blade pivot screw shouldvisible and accessible from th e outs ide . In the design gallery at the end of this guide w e showknifc that has a pivo t concealed b y the bo lsters and h an dle scales. While this certainly has a clea

appearancc, you must unscrew the bolsters and handle scales to adjust the blade play.W h e n sketching you r kn i fe, make sure tha t Ihe knife 's edge is f lush whcn c loscd and that

edges, for example the blade ramp, protrude from the handle. Furthermore, your knife shohave a consis tent l ine from the spine of the blade over the scales.This bas ic tmplate wi l l allow you to make m l t ip le va r i a t ions of the lockback lockm e c ha n i s m .

Begin your knife making with a sketch. Draw guidelines to determ ine the m ximum length of the blade.


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Design, Sketch, and a Functional Tmplate2.3 Creating a Functional Tmplate

Functionality of a Lockback Locking Mechanism

Function:Open: The locking mechanism pops into the noten with the l a tch . At the same time the

front edge of the locking mechanism serves as a stop.Open/Close: The lock is re leased. The latch runs on the radius of the blade base under spring

pressure.Closed: The blade base hits the inside of the locking mechanism. With spring pressureth e latch lies on the edge of the f a t radius and holds the blade in the handle.

With the construction of a lockback locking mechanism the knifemaker has various options. Thelocking mechanism can extendthrough th e entirebody and be operatedat the endof th e handle.Fo rthis, an appropriate notch is incorporated n he liners. Alternatively, a shorter locking mechanism ca nbe used that is operated from the middle of the handle. The exact position is a matter of taste.For a long locking mechanism there are numerous options for the design of the spring:1. The spring (round or f a t stock) s placed into th e locking mechanism on one end and restson a spacer or appropriate support pin on the other.2. The spring and locking mechanism form one piece. To ensure it has the functionality of a

spring, this type of locking mechanism mustbe made of the relevant material with the properheat treatment. The other end of the spring rests on the spacer or a support pin.

3. The spring (round or f a t stock) is placed into the spacer and pushed onto the lockingmechanism from the bottom.4. The spacer and spring form one unit. The spring pushes on the locking mechanism. Thespacer must be made of a material that can function as a spring.5. An additional option would be to use a coil spring that is placed into the spacer and workson the locking mechanism from the bottom.


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Design, Sketch, and a Functional Tmpl

Versin 1: Locking mechanism,spr ing, and spa cer are sep rateparts. The spring s placed in thelocking m echan ism an d rests f reelyon the lip of the spacer.Versin 2: The locking mechanismand spr ing form one piece. Thespr ing rests f reely on the l ip of thespacer.Versin 3: The sp ring s place d inth e spacer and runs freely along th elock ing mechanism.Versin 4: The spring s placed inth e lock ing mechanism and runsfreely on a stop (dowel pin, roll pin,etc.), which serves as a spacer andsecures th e liners.Versin 5: The spr ing and spacerform one piece. Under pressure,the spring rests on the lockingmechanism with a sl ight curve.Versin 6: Instead of a f a t spr ing orleaf spring, a coil spring is used. Itrests on the spa cer and p resse s onthe lock ing mechanism.Versin 7: Short locking mechanism.As an alternat ive to the long lockingmec hanism, you can use a short one.The control lever is placed near th emiddle of the handle.

A ll of these methods are suggested,but for our knife we will use a slightlycurved f a t spr ing that presses on thelocking mechanism and is held in thespacer with a notch, as in Versin 1above.


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Design, Sketch, and a Functional Tmplate

In principie it is best to make the spring a single component and place it in thespacer of the locking mechanism. You are not as limited in the materials youcan select for this part and the construction method is more fault-tolerant (withincorrect measurements of the spring you only have to replace this one part). Also,the spring is easily replaced should it happen to break or lose its springiness.In all of these versions the construction of the actual locking mechanismtherea of the latch and blade rampis identical.Open knife: The latch reaches into the noten of the blade and locks the blade. Thefront edge of the notch must rest as far forward as possible but not protrude overthe outline of the liner. The bac k edge of the notch (made at an 8angle) is theactual contact surface during locking. At the height of the pivot center it shouldbe positioned closer to the back edge.Closed knife: When closing the knife the lower surface of the latch lies spring-loadedon an edge on the base of the blade and presses the blade into the frame. Thisedge must rest in front of the blade pivot (toward the tip of the blade). The fartherforward the edge is worked in, the stronger the blade is held in the frame (due tothe leverage). The depth of penetration for the latch can also be relatively freelychosen. On one hand, the ock should secure. On the other hand, the lever mustbe moved this way (here the position of the notch, the gear ratio, plays a roll onceagain). For us, the depth of penetration is approximately 2.0 mm. To have more playwith the adjustment, we will make the notch in the blade somewhat deeper so thatsome space remains between the latch and the bottom of the notch. For our knifethe latch should sit approximately 2.0 mm deep n the notch. To provide sufficientstability, the width of the latch should be approximately 5.0 mm.There are varying opinions regarding the correct angle of the surfaces. It isimportant to note that when the latch is in use, it moves in a circular motion. Ifone works exclusively with right angels, the latch could potentially get stuck onthe ramp, it will not pentrate farenough and getcaughtwhen opened. Therefore,the back edge must be at an angle. In our case we are using an angle of between8and 9.The front side of the notch is 90 In some knifemaking manuals a slight taper of 4to 5 is suggested for the back of the notch. However, because completing such asmall angle is quite complex without proper machinery, we have abstained fromdoing this for our knife. Restrictions in capacity were unnoticed.

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Design, Sketch, and a Functional TmpFirs t , ske tch your d e s i g n . Y o u d o n o t n e e d e x a c t m e a s u r e m e n t s . L a t e r w e will t es t the kniope ra t ion wi th a f u n c t i o n a l t m p l a t e . A s a ru le , the Icngth of the b lade in a f o ld ing kn i f e c a nbe longe r t han the hand le ( excep t for the so-ca lled "extensin kn i fe ") . Draw in the pivotstop pin.Leave space in the blade spine for the locking mechanism and in the spacer for the inclus

of the sp r ing . The re fore you m us t choose the w i d t h of the b lade appropr i a t e ly . W hen c losedblade s h o u l d no t reach too far toward the spine .W i t h t h i s ske t ch you sho u ld e s t ab li sh t he bas i c s t ruc ture o f your kn i f e . Once you hav e des ign , t r ans f e r the sketch to cardboard . Dur ing th is s tep consider the kn i f e ' s f u n c t i o n aa long wi th the b lade ' s o u t l i n e , lock ing m ech anism , the s top of the c losed b lade , the posi t ion meas u remen t of the spacer, th e shape of the blade r amp, and the posit ion of the blade pivot. Ys h o u l d a lso inc ludc a rough ske tch of the recess i n th e h a n d l e , wh e r e t h e l o c k in g m e c h a nwill later oprate.F o r th e f u n c t i o n a l t m p l a t e , u s e a n a d e q u a t e l y t h i ck and s t ab le ca rdboa rd . We will usextens ively t h r o u g h o u t t h e kni f e m a k i n g process . In addi t ion to serving as an opera t iona l tes ty o u r kn i fe , your t m pla t e sho u ld a lso g ive you a good feel for the e r g o n o m i c s of y o u r kn i fe

For a func t iona l tmplate, seprate th e handle an d blade and adhere to cardboard.


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Establ ish the posit ion of the blade pivot . As a ma keshif t pivot , we wil l use a tack on our tmplate. The pivot pointlocated slightly be low th e midline.C l u c t h c s k e t c h t o t h c cardboard a n d c u t o u t t h c tmplales t 'or t h c h a n d l e a n d b l a d e . W h ey o u c u t o u t t h e b la de , l e a v e s ome ma te r i a l a t th e en d to l a t e r test th e p o s i t i o n o f th e p i v o t anf in i sh th e outline of t he blade ramp. Position th c blade pivot ju s t be low th e midl ine of t he handto h a v e e n o u g h s p a c e for the l o c k i n g m e c h a n i s m n th e b ack o f th e h a n d l e .Place the blade pivot fa r e n o u g h toward the back so that the blade and washer havc a s uf f i c i ec o n t a c t s u r face . T he b la de c a n be s h or t e ne d i f y ou s c t t he p i v o t c l o s e r t o t he r e a r o f t he k n i fY o u w i l l ne e d to f ind a s u i t a b le c o m p r o m i s e . H e r e i s so m e h e l p f u l a dv ic e . T he d i s t a nc e from tb lade pivot t o t h e u p p e r ed ge o f th e h a n d l e s h o u l d c o r r e s p o n d a p p r o x i m a t e l y w i t h th e d i s t a nfrom th e pi v o t t o t h e f ron t e dge .Place a tack t h r o u g h th e h a n d l e an d b l a d e t m p l a t e i n th e d c t e r m i n e d l o c a t i o n an d p i vt h e b l a d e i n t o t h e h a n d l e .

Using a t a c k , assemble the blade and the handle p iece .

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Design, Sketch, and a Functional Tmpl

Position the blade as you would in a closed knife. If the tip of the blade extends beyond the length of the handle, shorit accordingly.

On the backside draw the outline of the cutting edge onto the handle when the knife is folded. Some space remains up to the bof the handle. We will usethis space later for our locking mechanism, spring, and the spacer, on which the spring is affixed.

Posi t ion the blade as you w o u l d in a closed k n i f e . If the tip of the b l a d e e x t e n d s b e yo n d tl eng th o f the hand le , shor ten i t accord ing ly by d ra w i n g the o u t l i n e for the c u t t i n g ed g e o n t o ti n s i d e of the l iner . T ha t is the m x i m u m s pa ce t h a t yo u will have for the l o c k i n g me c ha n i sth e spr ings , and the spacer . I f you d e t e rmi n e t h a t the space is too t igh t , you can a d j u s t th e b l aa t th i s po in t .T he n cut ou t the blade ramp a long th e ha n d l e . T h e b l a d e shou ld n o t o v e r l a p w he n th e k nis closed.Takc apar t your t mpla te aga in an d beg in p lann ing for the lock . The la tch s ho u l d ha v ehe i g h t o f 5 m m and engage 2 m m d e e p i n t o the no t ch in the blade . T o d o th i s d raw a cira r o u n d th e pivo t , the uppe r po i n t o f w h i c h i s 5 mm f rom th e sp ine of the b l a d e . L a t e r t h e l a twi l l run on th i s c i rc le when you open and c i se the blade .


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Left: So that the blade ramp (w hen the knife is closed) does not extend ov er the h andle, we trac e the o utl ine o f the handon the blade. Right: Cut out the blade along the line. This establishes th e rea we have avai lable for the b lade ramp.

A Multifunctional Part

In addition to locking th e open blade, th e l ock ing mechan ism assumes tw o otherfunctions:1 . Holding th e blade closed: The latch presses on the back edge of the radius,pulling it nto the handle.2. Locking th e blade when the knife closes: The blade rests on an edge of the lockbehind th e latch. Leave some mater ia l at the base of the b lade and the inside of thelock ing mechanism to make f ine ad jus tments to these parts.Al ternat ive ly , or to make up for mistakes during production, an addit ional stop p incan be placed into the l iners.

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Design, Sketch, and a Functional TmplTrace g u id e l in e s o u t l i n i n g th e no tch where the la tch will rest . Later yo u will see how the la tp u l s the b l a d e i n t o the h a n d l e w h e n the k n i f e closes. This can on ly w o r k i f the latch is a pply ipressure a t the blade p ivot . The re fo re , the la tch m u s t engage a t the b lade p ivo t when o p e n .D r a w a l i n e t h r o u g h t he c e n te r o f t he b la d e p i v o t , p e r p e n d i c u l a r t o the m id l ine o f y o u r k n iT he l a t ch shou ld lock 2 m m d e e p in the blade, so we t r ace another g u id e l in e p e r p e n d i c u l a r

the f i rs t , 2 m m below the t op o f the r a d i u s .

Sketch the notch. For this we draw a front and back boun dary Une. The front edge of the notch lies as far forward possible, but not beyond th e outline of the handle. From the top of the pivot, start by sketching th e back edge of notch, using the required 8angle.

Sketch th e radius wh ere th e latch will run. The blade pivot is the center point and the top o f the circle should start 3 mbelow th e spine of the blade.


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Design, Sketch, and a Functional TmplateThe latch shou ld en gage the hand le at an an gle of 8 to 9.With th e traced radius and our guidel ines , th e outlinc of the notch is comple te .C ut out the notch an d neatly cut a r o u n d the rad ius o n y o u r blade t m pla te , leav ing s omcardb oard in the low er r igh t hand crner. This is wh erc the closcd blade rests on the lock i

me c ha n i sm and will need to be a d j u s t e d .A s s e m b l e the bladc and hand le w i th the tack an d open the b l a d e to see how the blade locinto th e handle . Using the notch you j u s t cu t out , t race th e latch and the front section of tlocking mechanism on the inside of the handle .N ow fold the blade and f in ish sketching the lock ing mechan i sm. I t reaches backwards ovthe recess in the handle . Mark the fulcrum of the locking m e c h a n i s m , which is cise to tcenter of the han dlc . The po si t ion of this po int determ ines how m uch or l it tle forc is necessato relase the lock. The s tart of the s pr in g i s jus t behind th e fu lc rum.

Cut out the notch and the radius. Transfer th e notch from th e blade to the handle.


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Design, Sketch, and a Functonai Tmpl

In addition to making a cardboard tmplate,we suggest making another tmplate from aluminum or brass. In the above tmpwe made th e locking mechanism a seprate component an d connected it to the handle usng a dowel pin as a pivot.

Next we draw the spring that prcsses on the locking mechanism from below and the spaat the end of the handle.Y ou can also finish the blade lock on the tmplate. W hen the kni fe is closed the blade rash o u l d rest on the locking mechani sm at an angle. The cutting rea of the blade shou ldhit against th e locking mechanism. Piece by piece we complete th e blade ramp and lock

mechanism.Using th e tmplate, ad jus t the o u t l i ne if necessary. It is impor tan t to work as preciselypossible and make any adjustments at this stage, before you start constructing the actu al knIn particular, we mu st crate clean ju nctions between the handle and the blade when the knifopen. Precise measurements will also guarantcc that th e blade lock funct ions properly, locking

latch in the notch w hen the blade is open and se cu ring the blade against the locking m echa niwhen closed. In the open and closed position s the locking mechani sm shou ld neatly lock wthe back of the handle. If the latch does not engage safely when the knife is open, ad jus tbottom side of the kni fe correspondingly. Leave sufficicnt space for the mechanics.


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Correct Angles for the Notch

Carefu l l y adjust thecon ta c t sur fac e o f thela tch and notch. Thef ront edge of the notchis alw ay s at 90. For ourknife we us an 8 angleon the opposi te edge. BladetNotch

Advice: Al l of these design features affect each other rec iprocally. The refore , if you m a k e a n ychanges during construction, you must check all function s again!There are a few critical points where you should leave som e excess m aterial: the point w hethe latch locks into the blade (opcn) and the ramp w here the blade rests (closed). This isquest ion of method. Because we want to make a funct ional brass tmplate in addit ion to ocardboard tmplate, we have decided to work with temp latcs that are as precise as possible.Natural ly, you can also com ple te your knife 's design using a computer . If you have acceto the necessary hardw are and software, such as a CAD program, you can m ake accurate anfunc t ion ing moc k- ups of your de s ign . W he n m a k in g a lockback kn i fe il is very helpi'ul to havcfunct ional t mp la te to test and ad jus t . Cardboard is easier to work wi th and chcapcr than stcFinal ly , w i t h a func t ion ing t mpla te you can get a good feel for the ergonomics of your kni feW e will m a k e a brass tmplate based on the cardboard tmplate w c created. The brass offeadvantages; first, a d j u s t m e n t sare made more preciscly, Second, a brass tm plate is mo re durablIf you plan to use the same tmplate to make several knives, the initial additional expense fthe brass is r e c o m m e n d e d .

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3. Producing the LinersWorking With DoweisWhe n it comes to ac cur ate ly posit ioning the spring, locking me chanism, and space r,dowe t pins are used to f ix the se parts to the knife. Ge nerally, sc rew s are not alwa ysenough because they do not a lways hold the components in place. A dowel pin,how ever f ixes the comp onen ts in the correct positions.To accurately mount th e doweis, clamp and drill th e components that need to be f ixedin th e knife. Clamping th e components together at the same t ime al lows you to keepthe dril l ing angle consistent. Dril l under size because we will later ream to the exactmeasurement of the dowel pin.For 2.0 mm doweis, drill with a 1.8 mm and then reamto 2.0 mm. This guranteos that the dow el stays fast in the d ri l l hole.

The materials for our knife cut to size.


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Producing the Liners

Trans fe r the handle outline onto the handle l iner mater ial and draw the pivot .

Drill the pivot hole with a 3.8 mm bit.C u t the hand le l i ne r mate r i a l to size. Then transfer th e out l ine of your tmplate onto tht i t an ium p a t e and m a r k the posi t ion of the pivot .W e wil l later p r o d u c e a p ivo t wi th a 4 .0 mm diameter . For this we pre-dril l into both l inew i th a 3 .8 m m bi t and then ream th e dr i l l holes t o 4 .0 mm .


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Producing the Lin

Crease the drill holes with cutting oil before reaming them.

Ream the 3.8 mm hole to 4.0 mm exactly.


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Fix the two l iners toge ther by p la c ing a dowel pin th rough bo th p ivo t holes a n d a p p l y iinstant adhesive . Then t race the out l ine of the l iner onto the f la t s tock . Because w e h a n d lboth l iners at the same t ime , the pivot holes wil l la ter be placed exact ly across from each othand the pivot will not t i l t .N ow t h a t the l iners a re affixed you can cu t t hcm out of the metal . Fi rs t , use a hacksaw

make a rough c u t . Then use a drill press to dr i l l t he ma te r i a l ou t a l on g the marked edge of tliner. You can use a f re tsaw to cut out the r e ma i n i n g ma t e r i a l. On ce you have a rough cut the l iners , file the edges unti l they are s m o o th , f i n i sh ing t he ou t l i ne wi th a bel t gr inder . Finalf inish the edges wi th a gr inding sur f a ce l oaded wi th 240 g r i t ab ra s ive pape r .

Sketch the outline for the handle.

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Producing the Line

Fix the liners together witha dowel pin and instant adhesive. Then cut out the joined pieces.

Trace the outline for the handle once again with a brass needle.


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Clamp the liners together to cut the liners with The hacksaw gives you a rough cut of the liners. The precisia hacksaw. work foHows.

:*

Saw away asmuch excess material as possible so that you have less to file or grindaway.

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Producing the Line

The round inner contours of the liner are difficult to reach with a Cut through the remaining material with a fretsawhacksaw. Therefore,drill a series of holes, cise together alongthe outline.

Continu finishing the contours of the piece witha file.


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Alternat ively, use a belt gr inder (8 0 gr i t ) .

No matter how youmanagethe preliminarv work, neatly finish the liners by hand (up to 240 grit).

U s i n g you r t m p l a t e , t race th e f i nge r ta b t ha t wil l op r a t e th e l ock ing mechan i sm and fi leout . Aga in , th e f i n i sh ing wor k is done wi th 2 4 0 gr i t abrasive p ap e r u n t i l th e d e s i r e d ou t l i n ereached a n d n o f i l e m a r k s a re v i s i b l e .28


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Producing the Line

Transfer the position andshape of the finger tab from the tmplate to the liners.

Work out the finger tabwitha half round file.

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Clamp abrasive paper (240 grit) onto round stock with the same radius as the tab and file the surface.

Finally, grind the liners once more to achieve a cleansurface.

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4. Making the BladePlace the blad e tmp late onto the f a t stock and trace the ou t l ines . I f you are m a k i n g m l t i pknives, draw tw o di f fe rent blade ou t l ines .M a r k the hole f or the p i v o t on the stock as well. Then pre-dri l l the holes for the pivot wi th3.8 m m bit and ream to 4.0 m m . Assemble the tmplate once again and mark the blade ou t l inWith the help of a dowel pin,place the blade blank onto a liner and check your outline. I f thhe ight f i ts wi th the baek of the han dle , i s the length of the blade eorrect?

Transfer the blade outline and the hole for the pivot to the blade steel.

Like the pivot hole on the liners, pre-drill the hole with a After greasing with cutting oil, ream the drill hole to 43.8 mm bit. mm.

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Making the Blade

With a dowel, assemble the blade tmplate and mark the blade outline.

Trace the blade outline onto the blade steel.

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Making the Blad

Join the blade with the handle liner andcheck the outline of the blade before proceeding.

Inspect the blade outline with the knife folded aswell. The handle must cover the notch, the spine of the blade shoubeconsistent, and the tip of the blade should not extend beyond the back of the handle.

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Making theBlade

R o u g h cut the blade steel w i t h a h a cksa w o r cut-off whe e l , e s t a b l i s h i n g the shape of blade as you d id w i th the h andle l iners .

Like the handle l iners , use a hacksaw for a roug h cut on the blade.

Cutthrough the remaining m aterial with a frets

You ca n also drill a series of holes along the outline. A rough outline develops.

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Making the Bla

Remove excess material with a file and continu to work out the outline.

Another option for rough cutting the outline of your blade is usian angle grinder equipped with a thin cutting disc.


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Making the BladeLeav ing some excess mater i a l on the blade lock and the recess for the l o c k i n g m e c h a n i s mthis poin t wil l help you la ter w h e n you g o to f i n e - t un e th e func t iona l i t y of yo u r knife .

Use a belt grinder if avai lable, as it is faster than a f i le.

This s what your rough blade blank should look like. You can clearly see the leftove r material on the notch and baseth e blade.

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Making the Bla

T h e f i r s t s t e p t o c r e a t i n g a f u n c t i o n i n g l o c k i n g m e c h a n i s m i s t o d e v e l o p t h c b l a d e . W e wf i n i s h t h e l a t c h a n d t h e r e m a i n d e r o f t h e l o c k i n g m e c h a n i s m , a s w e l l a s t h e i n t e r i o r s u r f a c e sl a t e r s t a ge s . T h e f i n a l a d j u s t m e n t s t a k e place a f t e r h a r d e n i n g t h c l o c k i n g m e c h a n i s m , a p ro cet h a t m a y c a u s e d i s t o r t i o n s . A d j u s t m e n t s m a d e p r i o r t o h a r d e n i n g m a y n o l o n g e r be a c c u r aaf te r t b e p r o c es s . M a k i n g s u r e t h e l o ck i n g m e c h a n i s m f i t s o n t o t h c b l a d e i s l e s s co s t l y t h a n t hr e v e r s e m e t h o d .L i k e o u r t m p l a t e , w e f i r s t c r a t e t h e r a d i u s o n w h i c h t h e l a t c h w i l l run.T h e l a t c h s h o uh a v e a h e i g h t o f 5 m m a n d s i t 2 m m i n t o t h e b l ad e. Leav e a l i t t l c b i t o f s p ace and e s t a b l i s h t hr a d i u s a t 6 m m . T h e c e n t c r o f t h e r a d i u s i s t h e c e n t e r o f t h e b l a d e p i v o t .T o ach icv e a neat r a d i u s o n t h e t a i l o f t hc b l a d e , clam p i t onto t h e r o t a r y table o f a m i l l im a c h i n e . U s e a l o c a t i n g p i n f o r a clean a l i g n m e n t .

Clamp the blade ontothe rotary table.

Mili the radius on the rotarytable with an end mili.


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Making the BladeY ou can also file th e r a d i u s . To do th i s w e p r epa r ed a r o u n d t o o l to k e e p th e blade p i val igned wi th the cen t e r o f the r ad i u s . T he r o u n d t o o l has the sam e d i am e t e r as the rad iu s . S eve rm ar k i n gs on the t oo l h e lp yo u accu ra t e ly f i le and gr ind a long the rad iu s . F in i sh th e r ad i u s w i24 0 gr i t abras ive paper .

W e created a locating pin for filing th e radius at the base of The round tool helps us maintain th e shape of the radthe blade. during f i l ing. We added sever a ! marks on the tool to swhen the sha pe of the ra dius is comp lete.

Good results can be achieved with simple me ans .

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Making the BlaBecausc the latch of the lo ck ing mec hanism runs along the r ad ius , the b lade pivot m u s t bplaced exac tly in the center of the rad ius . Also, m a k e sure the sect ion of the ra d ius that contac

the l ock ing me cha nism is smo oth. You should not leave any rough file marks on the piece. Wrecommend f inishing with a 600 grit p ap e r or higher.N ow we will m a k e the notch. First , mark the notch's posi t ion us ing our tmpla te . Place th

blade on the handle and draw the front cdge of the handle on the blade. The notch eannot bposi t ioned in f ront of th is mark.The wid th of the notch is determinad by the d csircd wid th of the latch, 5 mm in our case. M aksure the front cdge of the notch is in front of the center point of the pivot so that the latch puls thblade into the handle when the knife is closed a nd holds it in place. Mark a guid eline across the h eigof the blade indicating the front edge of the notch. Mark a similar guideline extending from the bacedge o f the bottom of the notch to the pivot. This U ne should align with the center of the pivot.Ncx t , d ete rm in e the d ep th of the notc h. The latch should d ip down 2 mm , but leave som

extra space at the bottom of the notch to bct ter adjus t the la tch in later steps. The dep th shoube between 2.5 mm and 3 .0 mm, m eas u red from the top of the r ad i u s do w n .

R e m e m b e r t h a t thcangle of therearrampin the notch should be 8. W h e n y o u mil i , howevemili sharper th an th is because w e will removc more ma terial in subse quent s teps . U se a 4 .0 mend mili bit to produce a latch with a width of 5 mm.

To c lamp th e blade exactly level, m a r k a con tour l ine on the blade tha t runs perpendicu laryour previous guidel ines . C lam p th e blade along th is line in the vise on the milling machine. Firsmil i along the front edge of the notch to approximatcly 2.5 mm to 3.0 mm below the top of thradius . Then mili the rear edge of the no tch to the b ottom of the notch at approximately 8.So the la tch runs smoothly on the surface, touch up this rea us ing a file and abras ivc pap(u p to 600 grit). Tomaintain the angle on the rear edge, mark the angle on the blade and clamit in the v ise .Mark the dimensons for thenotch:

1. Front edge of the handle2 . Front edge of the notch

(must be behind the frontedge of the handle)

3 . Ex ten s i n of the pivotcenter (approximate endof the notch)4. Contour l ine (determines

the depth of the no tchan d serves as a referencepoint for c lamp ing theblade n the v ise)


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Making the Blade

Mli the front edge of the notchat a 90"angle. Mli the rear notchat an 8angle.

If you prefer to work without amili, you can file out the Mark a gudeline and clamp the blade at an angle to filenotch. Herewe arefilingout the front edge. Thevise holds rear edge.the blade in place and maintains the right angle.

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Making the Bla

Use a file to work out the rear edge. Th e vice helps once again.

Regardless of whether you use a mili or file, al l surfaces should be neatly finished by hand (up to 600 grit).

T he blade is now f i n i s h e d up to the inner curve , where the stop w i l l rest when the bladec l o s ed .


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5. The Locking MechanismFor the locking mechanisrnwe wl use R W L - 3 4 a n d 1.4034 as a variant . Thestee l type 1.403is also well suited fo r the vers in in whieh the lock and spr ing are ma de from a single piece. spr ings a re inser ted , any com m on b lade m ater i a l can be used for the lock ing m echa ni s rn .The locking mechanisrn should be at least as thick as the blade plus both washers . To avolengthy g r i nd i ng w o rk , t h e d i m e n s i o n s of the raw m ater ia l should be as c ise as poss ible to thme asu re me n t .Place the bla de loosely into yo ur l iner s and roughly sketch the out l ine s of the blade onto thlocking mechanism in the notch rea . A s before, leave a l i t tle excess m ateria l w hen w ork i ng othis section so you can m a k e ad j u s t m en t s l a ten

Here we temporarily assemble the blade with a dowel pin. Adjust the raw material for the locking mechanism accordinginside the handle outline.

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The Locking Mechanis

First, mark the notch and the base of the blade on the locking mechanism.

The marked material. This will later become the latch of the locking mechanism.


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The Locking Mechanism

Extend the traced l ine for the latch to the ed ge Mark a clamping guidel ine perpen dicular to the l ine you just markeof th e material .The front edge of the latch should dip down into the notch at a 90 angle. Mark a correspondguidel ine and work out the edge by f i l ing o r gr ind ing . Then mili o r file the bot to m of the la tFinish the f r o n t 90 edge w i t h a 600 grit abrasive papen

Clamp th e locking mechanism in using your long guidel ine.

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Mili th e front edge and the bottom of the latch. You could also file this edge .

Finish th e milled surfaces by hand (up to 600 grit) .A dju s t th e rear edge of the latch at an angle using th e noteh in the blade as a guide. Clamp thblade accordingly in th e milling machine or work out th c cdgc wi th af i l e . If working with a f i l e , it

best to clam p the blade in the vise with the help of a gu i de l i ne marked at an appropriate angle.Work step by step, regularly checking the fit of the latch in the notch . The latch should nod ip down comple te ly but s i t 2 mm in the no t e h . Final ly, f in i sh a ll mating surfaces of the latcw i t h abras ive paper (600 gr i t ) .

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Clamp the locking mechanism along the guideline and set the mli at an 8angte. Regularly checking the fit withnotch, youwill reach the correct dimensions for the latch.

Finish themlledsurfacewith abrasive paper. Again, use the blade to inspect the latch, testing the fit by joining the parts. The two parts should hold together wthoutassistance.


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Options for the Blade LockThere are various possibi l i t ies for the blade lock when th e knife s closed. With alockback th e locking mechanism usual ly serves as the stop, which mea ns that th enner outline of the locking mechanism and the ramp of the blade wo rk together.Alternatively, you can use a seprate stop pin. Both options nave advantages anddisadvantages. With the f i rst, when the knife is closed, the curve on the base ofth e blade lies on an edge on the inner surface of the locking mechanism. Becauseth e stop is not f ixed the locking m echanism moves on its pivotthe blade sudesalong the locking me chanism under pressure, which can lead to the cutt ing edgestriking. That is the classic c onstruct ion of a lockback kni fe.In place of a curve, you can work an edge into th e blade ramp so that th e bladecannot move the locking me cha nism beyond the stop and the cutt ing edge is keptaway from the spine of the blade. This, however, is expensive to do and requirescons iderable planning.The problem can be avo ided by using an additional stop pin where th e blade hits.The cutt ing edge ca nnot touch the back of the knife. We have decided on the classicvers in in wh ich the blade ramp hits the locking mec hanism at a certa in point. Forlockback knives that is a typ ical performance.

A d j u s t the latch and notch and f in i sh (up to 600 gr i t ) . Then , determine the po in t for tl c k i n g m e c h a n i s m p i v o t . The pivot is located in the center of the locking mechanism. Place tlocking mechanism into the l iners , secure the blade , and trace the outline of the l iners. Cisethe m i d p o i n t of the l iner draw a g u i d e l i n e . The posi t ion vares according to the amount of spayou w o u l d l i ke for lock ing and w h e t h e r the l o c k i n g m e c h a n i s m wil l be short (functioning at tmiddle of the hand le ) or long ( func t ion ing at the end of the handle). In our case the a m o u n tspace for locking on the blade amounts to approximate ly 2 mm; a 1:1 gear ra t io is suf f i c ien t


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Position the blade in the openposition and the latch engagesthe notch. Herewe fixed the locking mechanismwitha clam

Mark theoutside of the lockmechanism along the liner.

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Place the pivot on this centered guidel ine and at least 1 mm from the top edge of the lineFor the pivot we will use a 2.0 m m dowel pin. The pivot posit ion is marked and pre-dri lled w ita 1.8 mm bi t . Then, fix the locking mechanism into the desired posit ion on the l iners , whicare sti l l joined togcther and f inish dril l ing the pivot hole. Ream the hole to 2 .0 mm . Insert thdowcl and chcck the functionality.

Ro u g h ly m a rk th e center of the lock ing m echanism .

Pre-dril l th e pivot h ole with a 1.8 mm bit.

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Position and clamp the locking mechanism to adrilling jig anddrill through the liners.

Then ream the drill holes to 2.0mm.

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The Lockng MechanisIn the next step you wil l shape th e outc r o u t l i n e of the lock ing me c ha n i sm . Use the beg r in d e r to work a long th e t raced ou t l i ne of the handle l iners . You can also file the outl ine. Ia completely assembled state, f inish the parts and m a k e ce r ta in the oute r ou t l i nes of the l ineand lock ing mechan i sm a re cons i s ten t . You can p l an on tou ch ing these jun c t i on s up a f te r thl ock ing m e c h a n i s m i s harden ed . Tha t p rocess m ay d i s t o r t the d i m e n s i o n s of y o u r componentand/or depos i t a layer of scale.

Use the belt grinder on the outer outline.

The b lank is ha l fway f in ished. Before wo r k i n g on the inner outline, make sure al l surfaces are ground and finished.

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The Locking MechanismSwivel the blade into position an d trace th e cutting edge onthe locking mechanism. Now we have a general idea of wherewe should place our stop and how much space remains forthe spacer an d spring. \o

a t t e n t i o n to the blade out l ine when the k n i f c i s c losed. This will ind ca te the shape and lengof th e blade . You can no w see how m u c h space you will need for the l o ck i ng m e ch a n i s m, s p ri nand spacer . Mark the out l ine of the cut t ing edge wi th the blade c losed.Es tab l i sh a n edge where y o u wil l l a t e r i n s e r t th e s p r i n g . T h e s p r i n g s h o u l d f u n c t iapproximatcly 5-10 m m beh ind the pivot, ei ther as an i n t e g r a t e d co mpo n e n t , in w h i c h tl o c k i n g me ch a n i s m and s p r i n g fo rm one un i t , or as seprate piece to insert .At this point you should chose whether the spring is fixed in the spacer and is operated on locking me ch a n i s m, or, like in the versin we present here, th e spring is fixed in the locking mec hanand func t ions on the spacer. The advantage of this solution is that it requires less operating forFor a secure locking mechanism the power of a slightly pre-stressed spr ing is co mp letely suffic ieChoose a spr ing tha t is as long as possible to mi n i mi z e stress on the piece. W e should notha t your spr ing mater ia l should be slightly pre-s t ressed. Take the space requi rements ina c c o u n t and choose the shape of the spacer accordingly.Sketch th e spacer, which will incorprate th e spr ing in a later step. Now, m a r k th e recessesth e l ine rs tha t opra te the spr ing. The th ick ness of the lock ing mec hanism should mask theseLater w e wil l develop the blade lock. Therefore , as a precaut ion, w e wi l l leave some excmaterial behind the l a t ch .The inne r ou t l ine o f the lock ing me chan i sm i s now com ple te . D r i l l along t he out l insepra te the re m ain in g m ater ia l wi t h a saw, and mil i the surface f a t . Because the end of lock ing mechan i sm moves around the pivo t in a c i rcular p a t h , m a r k th e r a d i u s a c c u r a t e ly wa compass . This prevens gaps tha t wi l l a f f c c t the kn i f e ' s opera t ion.


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Mark the inner outline. Make the back section of the locking mechanism so that sufficient space remains for a spring. the front rea leave enough material to make later adjustments on the blade lock.

Drill a row of holes along the outline to remove the material.


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Milling th e inner outline. A file or belt grinder can also be used.Touch u p th e outline s with a belt gr inder and f ine- tune th e edgcs with a file and abrasive paperN ow assemble the spring. Guide l ines help c lamp in the locking m echanism so you can dril lvertical ly as poss ib le . Depending on the shape of the locking mechanism, th e length of the dbit , and the size of the chuck, you may not be able to drill at a r igh t angle. But t h i s is i r releva

because the spr ing can be appropriately bent af tc rwards .For the spring we will use 2.0 mm round s tock. Therefore we will drill our holes with a 1

mm bit and t hen ream to 2.0 mm. Firs t , t em porari ly inser t the spring.

Mark the end of the locking mechanism with a compass .


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Roughiy preparethe inner outlinewitha belt grinder.

Touch up the locking mechanismwitha file, then precisin grind by handwith abrasive paper (up to 400grit).


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Sketch th e locat ion of the drill hole for the spring . I t may not be possible to dril l a perfectly perpen dicular hole from aboTo determine this be fore you start drilling, place a rail a long the marked drill hole.

T o tes t operat ion and f i t , fix the s l igh t ly pre-stressed spr ing with a small bar c lamp.necessary , you m ay need to to uch up the locking m ech ani sm piece . T his is especia l ly t ruc fth e lock. Does th e latch catch while c losing , does it run neat ly on the b lade ramp? For idefunctionality precis in gr ind th e surface w i t h 600 gri t o r higher .


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With anextended 1.8 mm drill bit (the drill chuck must be able to go past the end of the locking mechanism) drill thole for the spring.

To support the assembled spring temporarilytspacer will eventually serve this purposeuse a bclamp. Now you cantest the operation of your knife

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6. The Blade LockW o r k c a r e f u l l y a n d u s e sma l l s teps w he n m a k i n g a d j u s t m e n t s on t he va r ious c o m p o n e n t syour knife. Regularly checking how the knifc works is important. With the next steps you mud e c i d e h o w a n d whcre t he b l ade wil l be d r a w n i n t o t h e k n i f e and re t a ined w hen c los ing .A s p r e v i o u s l y mentioned, there a r e tw o v e r s i o n s :1 . Stopped on the locking mechanism: I n I h i s versin the blade is in di rect contact w it he bo t t om edg e of the l o c k i n g m e c h a n i s m . R e m e m b c r that w e left excess m at e r i a l on tl o c k i n g m e c h a n i s m to m a k e a c c u r a te a d j u s t m e n t to th e b l a d e . E x a m i n e th e p r o p o r t i owi t h y o u r f u n c t io n a l t m p l a t e . Y o u m u s t p a y a t t en t ion to severa l p a r a m e t e r s s i m u l t a n e o u sw i t h these steps. F o r e x a m p l e , w h i l e a d j u s t i n g t h e b l a d e r a m p w it h t he edg es in t he lock im e c h a n i s m , y o u m u s t also apply prcssure on the blade , t r ig g e r ing th e l a t c h to p u l i t int h e h a n d l c . A d d i t i o n a l l y , th e u p p e r e d ge of the l o c k i n g m e c h a n i s m , w h e n o pe n a n d c loss h o u l d b e f l u s h w it h t he hand le .2. Ad ditional stop pin: F i r st , c o n s i d e r w h e r e s u f f i c i e n t s pa c e r e m a i n s for a stop pin. Y o u cplace i t be h in d t he b l a de p ivo t w i t ho u t any prob lem s. M ark t he de s i red loca t ion beforehaa nd m a k e s u r e a d j u s t i n g th e base of the blade does n o t h a v e a d i s r u p t i v e a f f e c t in thspot w h e n opcn. To a c c o m m o d a t e a s u i t a b l c d o w e l pin with a 3 .0 mm d i a m e t e r , p r e - d rwith a 2 .8 m m b i t a n d t hen ream th e h o le s to 3 .0 m m . G r i n d th e base o f th e b l a d e u nthe s top fits. N ow , ad j us t t he ou t l ine o f t he lock ing m e chan ism in bo t h ope n and c lospos i t ions onto th e l iners . Tip: This versin c a n stil l save a k n i f e w h e n th e stop above tl o c k i n g m e c h a n i s m i s not s u c c e s s f u l .Advice : I f toomuch material is removed from the bas e of th e blade, th e locking mechanism willreach too far into the liners. To make c orrection s you must a djust the liners accordingly.

Make fine adjustments to the parts by removing material with a belt grinder. But make sure you leave enough matefo r subsequent adjustments.

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The Blade L

Draw in helpful guide points. Th e ar row on the left marks th e locat ion where th e f o r c of the spring pushes th e lainto a stopped position wh e n the knife is closedthis pushe s the blade into the hand le. The rear edge beh ind the laserves as a stop for the blade.

Draw in h e l p f u l gu ide po in t s on t h e b l a de . The f ron t p o in t m a r ks t h e rea wher e t h e l a ts h o u l d p r e s s to p u l in the b l a de . Th i s edge may not be r e m o v e d . T h e ba c k po in t m a r kspos i t ion wh er e t h e b l a de h i t s . He r e w e rem ove m a t e r ia l un t i l the b l ade is in the h andl e and lock ing mechan ism i s s i m u l t a n e o u s l y u s h w i t h th e back of t h e h a n d l e . T h e r a d i u s in be twcis necessary so the b l a de can move f reely.

A dd th e markings and grind th e r a m p on a contac t whee l . P roceed car e fu l l y and tes tope r a t ion a f t e r each work s tep .

Step by step work towards th e appropr ia te outline. Keep in mind that your parts stil l need to be precisin groundto 600 grit) . Therefore, continu to leave some excess m ater ia l. One point to note: with 0.1 to 0.2 mm of excess mateth e latch is still not f lush with th e handle.


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7. Making the SpacerImportant Information Regarding the SpacerThe spacer in a lockback mechanism can have many functions. Dependng on the knife's designa spacer can havetwo basic sty es. If the space r o ins the hand lesca les and addi t ional ly servesas a suppor t o r secure mounting for the spring, this must be taken into considerat ion dur ingdesign. I f the spring re sts on an add it ional s top pin inco rporated into the knife, you are lessrestr icted with the d esign o f the spacer. This prod uces a knife with a more open back. You cansecure the spa cer in var ious wa ys, reg ardless of whether you use a roll pin.1. First, drill a clea ran ce hole throu gh the spa cer. In one side of the l iners dr i l l a clear an ce hole( w i t hac oun t e r bo r e ) , i n t heo t he r a thread. You willfixthe liners and the spacers together with thisscrew and possibly several other screws. In addi t ion, pin the spacer fo r exac t positioning.2. Dril l a thread into the c le aran ce holes in the s pacer and l iners. From both sides the spac eris screwed together with the l iners. You should pin it as wel l .

In o u r k n i f e the spacer a ssume s two func t io ns : i t combine s the l ine rs and a t the same t imserves as a s u p p o r t a n d w o r k i n g p o i n t fo r th e s p r i n g . We use the RWL-34 ma te r ia l tha t wil at e r be ha rden ed . The t h i c k n e ss i s equal to tha t of the b lade plus bo th wash er s . Use the moappropr ia t e fat stock so you do not have to spend a lot of tim e f at g r i n d i n g .O n t he i n n e r sur face of the l i ne r , m a r k th e rea w h ere the spacer shou ld be located. M a rthe spr ing support on the spacer and wor k out this edge (saw, f i le , mil i , e t c . ) . Now, tem pora r i l

f i x the spacer onto the l in ers with the hclp of a bar c lamp. In the correc t posi t ion the spr inshou ld b e n d forward s l ight ly (if i t does not you s h o u ld b end the s p r i ng accord ing ly ) and thspacer s h o u ld be f l u s h to the end of the l o c k i ng mec h a n i s m. Br ief ly tes t th e o p e ra t i o n .

Mark th e rea where th e spacer, spring, and locking mechanism ar e located . Then m ark th e rea that rem ains when thblade is closed.


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Making the Spa

Assemble the locking mechanism andspring. Determinethe dimensions of the recesswhere the springwillbepositionand mark it.

Mli out a small notch in the spacer (you can also use a file).


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Making the Spacer

Fix th e spacer with a clamp and test your knife with th e spring in place.W i t h th e spacer still clamped, dril l and ream th e holc for the first dowcl pin th rough t he spacand bo th l i ne r s (1.5m m dowel p i n ) . Transfe r th e ou t l i n e of the h a n d l e end on to th e spacer an

fi x the spacer with ano t he r dowel pin.In add i t ion , drill a clearance ho le for the l iner serews. Foth i s one place a count erbo re, the other receives a th read . To dr i l l the th read accura te ly , we usan a u x i l i a r y de v i c e to keep th e hole ver t ica l . You can use t h i s a u x i l i a r y e q u i p m e n t la ter w h edri l l ing for the h and le scales.

Above: Drill the spacer with the liner using a 1.3 mm bitLeft: Ream the hole to 1.5 mm for the dowel pin.Do nforget to use cutting oil.


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Making the Spa

The spacer with the dowel pin in place. The spring is bent slightly upward.

Place the second dowel pin and drill a clearance hole for an M2 screw.


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Making the Spacer

Mount the spacerand trace the outlines of the handle and the blade. Remove some more material from the cutting rso the cutting edge does not bump against the spacer later.

Roughly cut the outline with a hacksaw.

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Making the SpacF i n i s h th e s h a p e of the spacer , u s i n g a h a c k sa w fo r the p r e l i m i n a r y w o r k . W i t h t h e d o wpin s p laced i n t h e l i n e r s , u s e t h e be lt g r i n d e r to work o u t t h e o u t l i n e o f the h a n d l e .A s m e n t i o n e d before , i n s p e c t th e d i m e n s i o n s fo r your spacer a n d l o e k i n g m e c h a n i s m tw i d t h s h o u l d be e q u a l to the blade th ickness p lu s tw o w a sh e r s . T h e th i c k n e s s of the sp a c e r m ube exac t , o therwise th e f rame wil l no t be s t ra igh t and th e k n i f e wil l n o t f u n c t i o n properly. Us e

abras ive paper on an even base , l ike a pan e o f g lass , to f i n i s h th e f a t su r faces o f these pa r t s .Y o u r f ina l a d j u s t m e n t s to the l o e k i n g m e c h a n i s m wil l t ake place af ter th e h ea t t r ea tm eprocess to a d d r e s s p o s s i b l e d i s t o r t i o n .T h e l o ek i n g m ec h a n i sm sh o u l d m o v e ea s i ly bc tw een t h e l i n e r s .

Left: Use a belt grinder to f in ish th e spacer 's outline.Below: The drilled spacer. You will precisin finishw o r k by hand later w h e n it is mounted.

Grind th e spacer an d loekm e c h a n i s m to the s athickness on a cup grindm a c h i n e . U s e l e f t o vmaterials to hold your knin place.


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8. Grinding the BladeFix the blade to the k n i f e f r a m e w i th a dowel pin . Then open th e k n i f e an d m a r k the eof th e g r i n d and the spot where the grin din g should proceed to the ricasso. You can g r i n d t

m a r k s o ut later.N ow m a r k the center of the blade on the u n d e r s i d e of the blade. This wil l l a te r becom e tcu t t i ng edgc.Tip: Tracing against th e grind line is more visible. Grind lightly over th e underside ofthe blade.

Mark the end of the grind on the blade with a marker.

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Grinding the Bla

To make sure the markings are parallel on both sides, clamp the blade into a vise and trace along the vice pads on both side

Using a height gauge, mark the center of the blade, which will become the cutting edge.


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Grinding the Blade

The marked blade. The next step of the process takes place at the belt grinder, but you can also use a file.

Grinding the bladeU se the belt grinder to surface grind the b lade , ex tcnd ing the grind co n t i n u o u s l y to the sp iof thc b lade. This produces a f a t g r in d in g angle and enhances y o u r knife ' s cu t t i n g proper t i eStart with a coarse abrasive belt (60-80 gri t ) . For the precis in grinding use a flexible be(150-240 gri t) that you can place in to the r icasso. Make sure that the edges do not wear awaY ou can also use a file and an abras ive block .Leave between 0.2 mm and 0 .5 mm of mate rial on the cu t t ing edge. Y ou wil l f in i sh gr ind ithe blade after the blade is ha rd en ed .

Your roughly ground blade should clearly show that you have adhered to the marked boundaries.

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Grinding the Bla

Complete th e precis in gr inding and f i n i sh in g by hand, s tar t ing w i t h 24 0 grit and w o r k iyour way to 400 and then 600. Do not forget to grind the spine of the blade.Work carefully at the junct ion from the spine to the notch. The edges mu st remain sharp and shounot be worn down. You may f ind it helpful to finish th e g r in d in g after your knife is assembled.In addition to the blade , gr ind the lock ing me chan ism w i th 600 gr i t. Once al l of yocomponents are hand- ' inished take them to be hardened at a heat t reatment shop.

Place th e blade in a vise and cont inu th e f inishing work by h a n d with an abrasive block.

When gr ind ing , pay careful attent ion to the edg es so you do not we ar them down.


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Grinding the Blade

Bla de , lock i ng m e c h a n i s m , a n d s p a c e rr eady for the heat trea tmen t shop.

Four Tips for Finishing A high quality abras ive paper will last longer and alow you to ach ieve a better f inish. Before sw i tching to the next f ines t grit, the f inish must be f law less and even . Each t ime you sw itch to a fne r gri t , change the dire ction you are grinding in. Grinding sdone b est gr i t by grit at a 90 angle to the previous grade. Pay attention to cre ating neat, c lean edges (especial ly the junct ion to the r icass o along th espine of the blade). Do not grind round.

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9. Making the BolstersA s mentioned earlier, there are various options for m a k i n g th e bolsters. W e wil l concntrate on versions in which th e blade pivot extends throug h th e bolstcrs and is thus accessible externally. Tbolsters a re mou nted w ith tw o secure dowcl pins. The blade pivot m ainta ins the construction.Alternatively, you can conceal the bla de pivot. For this a notch is inclu ded on the inner su rfaof th e bolsters that incorporates th e blade pivot. The bolsters are thcn scrcwcd together with tl incrs. You can also use continuou s h an dlc sea les w ith ei ther a hidden or visible blade p ivo t .C ut the raw mate r ia l to the appro pr ia te l eng th . La te r your bo l s te r s should have a taperr a d i u s to jo in c lean ly w i th the h a n d l e sea les . Mark th e ccnter on the l incr and t race the r a d i

onto the l iners w i th a c ompa s s .With the aid of the l iners sketch the o ut l in es of the bols te rs and m a r k the dril l hole for tpivot. Leave suf f ic ient ma te r i a l for the r a d i u s .For a 4.0 mm pivot , dr i l l f irst wi th a 3.8 m m bit and ream th e dri l l hole to 4.0 m m . Fix tbols te r s toge the r w i th ins ta n t adh es ive o r a ba r c l amp so tha t the d r i l l hole is pe rpend icula r aboth bols te rs a re dr i l led out s imu l t aneous ly .Wi t h a 12.0 m m coun terbore , dr i l l a hole on both s ides w here the blade screw sho uld hi t tbot tom. Leave 2.0 mm on the bottom to be able to inse r a dowe l p in , w h ic h wi l l la ter se rvea locking device for the pivot .

Transfer the planned outl ine of the bolsters from the sketch onto the liners.


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Making the Bolsters

Place the liners on the bolster material, mark the outline, and then drill the hole for the pivot.

Drill the pivot hole. Fix the bolsters to each other with instant adhesive anddrill through both pieces at the same tim

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Making the Bols

W i t h a dowel p i n , f ix both bols ters on a l i ne r and t r ace the o u t l ine . To m a k e a rough cut of the shape, use a cut-off wh e e l t r ien co n t inu work in g ou t the shape on the bel t g r inder .Dri l l a cen te r ho le th rough bo th l ine r s on the marked location so t h a t you can c lampl i n e r s toge thc r wi th tb e bo ls te r s o n t he ro tary t ab le later.Because you wil l a t tac h th e bolsters secu rc ly with tw o p i n s (1.5 m m ) , prc-dril l into th e l inwi th a 1.3 mm bi t . Make sure the dril l holes are outside the n o t c h of t h e b l ad e p ivo t .Sep ra te th e liners an d bo ls te r s for the r igh t an d left sides an d m o u n t th e bo ls te r s on t ol iners , st ra ightcn t hem , and c o n t i n u dr i l l ing t h r o u g h th e exis t ing dr i l l holes . Th en ream to m m and p in t he bo ls te r s to the l ine r s .C l a m p th e l ine r s wi th th e p inned bo l s te r s to the ro tary tablea dowel p in t h r o u g h th e c e nhole serves as a cen te r ing tool . Now, mili th e rad ius wi th a 90 end mili an d t h e n th e anglesth e n o t c h w i t h a 15 dove ta i l mil i .Remove the bols ters from the l ine r s and nea t ly g r ind them . A d j u s t the h e igh t o f the bo l s ton the l ine r s us ing a file and abrasive paper .

Ream th e drill hole to the required d imensin of 4 .0 m m.


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Making theBolsters

Set your counterborewitha depth stop andmli into the notch for the pivot onbothsides. Your counterbore should bdeep enough to include the entire pivot head according to the radius of the bolsters. We are using a depth of 2 mm.

Transfer the outline of the handle onto the bolsters witha scriber.

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Making the Bolst

Make the prelimnary cutswith either anangle grinder or ahacksaw.

Work out the outline of the bolsters with a belt grinder.


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Making the Bolsters

After the belt grinder your bolsters with the notch should look like this.

Dowel pins are required to fix the bolsters to the liners in a later step. Here holes are pre-drilled into the liners.

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Making the Bolste

Fix the bolsters in the proper position on the liners with a dowel pin and instant adhesive. Pre-drill through the lineDo not drill to deep because the bolsters will berounded off later.

Ream the drill hole through the liners and bolsters in one step.


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Making the Bolsters

Match up the liners and bolsters accurately and pin them together.

Now drill and ream a hole to center the piece on the rotary table.

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Making the Bo/st

Securely clamp the piece and start milling the radiuswitha 90" endmli.

Use a 15dovetail mli on the side for the handle junction.


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Making the Bolsters

The undefined bolsters. Remove the burrs after milling.

T o curve the bo ls te rs, c lamp thcm in to a ux i l i a ry equ ip me n t on the belt grinder. U se 80/15grit on the grinder f o l lowed by an abras ive b lock and papcr. Neat ly round th e cdges for a more f ined l ookFinish the bols ters by ha nd , ro un di ng the edges and gri nd ing the o ut l ine wi th abras ive pap(200/400/600) . On the s ide w here the blade pivo t w ill later be located, dri l l and ream a ho le fthe dow el p in , w hich w i l l s erve as a lock ing device for the p ivo t . A f t e r th i s send the bols ters

a heat treatmcnt shop.


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Making the Bolste

Round the bolsters on the grinding equipment.

A view of the grinding from above.


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Making the Bolsters

Drill and ream a hole for a locking device (dowel pin) in the pivot.

Adjust the bolsters on the liners, round the edges, and finshwithprecisin grinding.

S2


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10. The Blade PivotW e w i l l m a k e th e p i v o t o u t of a s o l i d p i ec e of t i t a n i u m and f i n i s h i t on th e l a t h e . I f t he q u i p m e n t i s no t av a i l ab l e , you ca n use e i t h er p r e fab r i c a t ed p ar t s o r i m p r o v i s e . F o r ex am pyou can m ak e p i v o t s f rom v ar i o u s o r n am e n t a l s c rew s .M at er i a l : I f y o u u s e s tee l fo r t h e p i v o t , i ts h a r d n e s s s h o u l d b e a p p r o x i m a t e l y f i v e to tR o c k w e l l l ev i s b e l o w t h e b l a d e . U s i n g u n h a r d e n e d s t ce l s h o u l d b e s u f f i c i e n t h a r d e n iincreases th e r i sk o f d i s t o r t i o n an d d o e s no t of fe r an y a d v a n t a g e s w h e n u s e d in lo w s t r ec o n d i t i o n s . A l t e r n a t i v e l y , b r a s s , t i t a n i u m , a n d b r o n z e a r e also s u i t a b l e . If d e s i r e d , y o u c a n au s e a s t ee l p i v o t a n d s e t a b r o n z e b u s h i n g i n t o th e b l a d e . T h e a d v a n t a g c h er e i s t h a t t h i s c r eaa s e l f - lub r ica t in g b l a d e m o u n t i n g , h o w e v e r , th i s requi res great prec i s in an d m o r e s t ep s .To ge t s tar ted on the pivot , f i r s t , d e t e r m i n e i ts l en g t h . T h i s d i m e n s i n s h o u l d be the t h i c k n eof th e b l a d e , w a s h e r s , t h e l i n er s , a nd the b o l s t e r s . Y ou m u s t a l s o c o n s i d er th e d e p t h of tn o t c h es i n t h e b o l s t e r s . I n o u r k n i f e they are 11.5 m m .N ow there a re t w o p o s s i b i l i t i e s :1 . W e work on the f i t . T h e l en g t h o f t h e p i v o t c o r r es p o n d s t o t h e ab o v e b as e m ea s u r e m eT h e en d o f t h e p i v o t i s c x ac t l y f l u s h w i t h th e b o t t o m o f t h e c o u n t er b o r e i n t h e b o l s t eT h i s r e q u i r e s e x t r e m e l y a c c u r a t e w o r k . T h e b l ad e ac t i o n o f a c o m p l e t e d k n i f e c a n nb e a d j u s t e d w i t h o u t a g re a t d e a l o f m o d i f i c a t i o n . T h e c h ar m o f t h i s v er s i n i s h av ie v e r y t h i n g f i t exactly.2. The pivot ends approximately .05 m m below the bottom of the counterbore. T h i s g i vus s o m e play d u r i n g p r o d u c t io n . T h e b l a d e play ca n be a d j u s t e d l a te r b y r a i s i n g th e pivw i t h th e screw.In contras t to the f i rs t o p t i o n, w i t h t h e s ec o n d v er s i n a l o c k i ng d ev i c e i s ab s o l u t e l y n ec es s ae i t h er w i t h p o s i t i v e l o c k i n g or by a d h e r i n g th e p i v o t w i t h a t h r ead l o c k c r . In t h i s p r o j ec td e c i d e to use a d o w c l pin as a p o s i t i v e lo c k i n g d ev i c e . F o r t h i s v er s i n th e l e n g t h f or the p i vis 11.0 m m .Firs t , c l a m p th e t i t a n i u m b l a n k i n t o th e l a t h e . Then d r i l l a n M 3 i n t e r n a l t h r ead . Tm a t e r i a l c an b u l g e f r o m t a p p i n g , b u t y o u c a n t ak e c a re o f t h i s l a te r w h e n y o u t u r n t h e p i eo n t h e l a t h e . F o r t h i s w c d r i l l a c e n t e r h o l e t h e n th e c o r e h o l e a n d t h e t h r ead . T u r n th e s hof t h e p i v o t t o a d i am et er o f 4 . 0 m m f i r s t , a n d t h e n t u r n t h e h e ad o f t h e p i v o t t o 1 2 .0 mW o r k i n s m al l s t ep s an d t e s t t h e m e a s u r e m e n t f r e q u e n t l y , p l a c i n g t h e b l a d e o n t o t h e s h a f tth e p i v o t a f t e r eac h s t ep .


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The Blade Pivot

Using a lathe, place a center hole in the ttanium pivot.

Drill the thread after drilling the core hole.

Then turn the pivot to the desired diameters.

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The Blade Pi

Carefully turn the piece, regularly testing its diameter with the blade.

Finally, seprate the pivot from the rest of the material.

Now clamp what remains of the titanium blank and strip the front end.


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The Blade Pivot

To make the screw end o f the pivot, turn the blank to 3.0 mm in diameter an d then cut the thread.Co mp lete the screw end of the pivo t (screw head 12.0 m m, thread diameter M3). Then clamboth turne d par t s, and tu r n the m ilat to the correct length. For th i s knifc both ends of the p ivare slightly counterbored in the bolsters.N ow drill five holes in the head of the screw end of the pivot . Mak c sure you do not dri l l thcounterbores too deeply so the holes do not push th r ough the bottom of the pivot head.To com plete the lock ing device, place the p ivot int o the bolsters. T he pr evio usl y drilled holmak e a recess on the i

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