Pocketknife Making for Beginners

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Translated from Germán by Ingrid Hlserand Jolin Guess.

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. CONTENTS

A FewWords Up Front 4

1 Preparation. 1 In General 8

.2 Choice of Materials 9

.2.1 Blade Steel IO

.2.2 Materials for Handles and Other Parts 13

.3 Tools 14

.3.1 The File:The Most ImportantTool 14

.3.2 Sandpaper/Abrasive Cloth I 7

.3.3 Working with Alignment Pins and Drilling Holes 18

.3.4 Washers 18

.3.5 Vise 21

.3.6 Drill Press 21

2 Slipjoint Folding Knife2.1 Designíng and Drawing aTemplate 22

2.2 Working on the Handle 33

2.3 Creating the Blade 38

2.4 Construction of the Backspring 54

2.5 Finishing theTang 64

2.6 Precisión Work on the Blade and Spring 70

2.7 Intermedíate Check and Washers 72

2.8 Handle Scales 772.9 Assembly and Finish 83

2.10 Variations 88

2.10.1 Blade Tang 88

2.1 0.2 Pivot Variations 90

3 Friction Folding Knife3.1 Designing and Drawing aTemplate 92

3.2 Creating the Blade , 96

3.3 Working on the Handle 98

3.4 Grinding the Blade I IO

3.5 Connecting the Ferrule with Blade and Handle 113

3.6 Assembly and Finish 120

6 A FewWords Up Front

Constructinga folding k n i f e using only a few machines and tools wasa new technical frontier for me. Prior to all the ertbrts that go into thefinishing process, I'm otherwise used to using all the great machinesthat are surrounding me in my workshop. Giving up these habits andusing simple tools instead wasn't always easy for me.

Rut this is exactly what keeps us going: new challenges, shapes, andmaterials. If yon are using this book to tackle folding knives, you'llsee howcomplex the whole issue is. But don'I be afraid: it will all t u rnout wcll—in a vcry pivotal sense.

F.ven Peter sometimes was keen on trading his camera for a file. I hopethat I don't lose him to the knifemaker's world because oí our bookprojects. He ought to stay with us as a photographer and aulhor.

Stefan Steigerwald

A FewWords Up Front 7

After describing quite complicated knife projects in the last fewvolumes, this time wc wanted to come up with something simpler withrespect to construction, and simpler and quicker in manufacturing—uti l i ty knives that can bebuilt without a big collection of power toolsand machines.

Although a slipjoint folding knife looks quite simple at first glance, asyon start understanding the design, you realize that its not that easyat all because here—similar to a backlock—the backspring fulfillsseveral íunctions at once.

As usual, we have documented every step of the process and ratherthan omit anything, wc e ven added descriptions oí intermedíate steps.Whoever íbllows the manual step by step and uses a témplate befo restarting to build at random will soon hold a functioning slipjointfolding knifc in their hands.

But my favorite among these knives was only found towards the endof the production: it's the friction folder. Out of a blade, a strip ofmetal, a piece of wood, and a few rivets, a usable pocket knife wasconstructed quite rapidly.

Among pocket knife enthusiasts, I belong to the "mechanics faction."1hc more complicated the locking mechanism, the more interestinga kni fe is to me. Usually. The friction folder is the exception. A knifethat has just the necessary parts has a special charm that you canhardly escape.

Such a knife is also rather quick to build. The material doesn't have tobe expensive and with the exception oí a drill press machine and a tewfiles and sandpaper, no tools are used beyond common shop tools. Inaddition to this, a friction folder is very lightweight—the ideal knifefor a little snack between work. Rye bread, ham, and the homemadefolder. Have fun and bon appetit!

I'etcr Fronteddu

Preparation

I. I In General

With respect to building a slipjoint, as well as a friction folder, thereare different approaches. We settled on using as many simple tools aspossible—not the big industrial machine shop toys that Stefan Steigerwaldis used to. But this approach may not be for every interested knifemaker.Slipjoint and friction tblders are unspoilt, simple conslructions. Manytraditional pocket knives have been manuf actured in this style for decades,maybe even centuries—like the Laguiole in Franco or the Resol/a from

Sardinia. And as simple and very reasonable utility knives, they slill proveto be successful nowadays, despitc new technological developments.

Compared to linerlocks or backlocks, these knife types require fewerparís ibr construction. Thc friction folder, in particular, doesn't demandthe tight tolerances that have to be kept with complicated lockingmechanisms. The knives were riveted at the handlc and the pivot, theywere not—as Stefan Steigerwald usually does—screwed togelher. The

tight fit is accomplished by means of vigorously hitting the rivets. Somc

parts, the clarap or blade pivot, íor example, were made from whatevcr

happcned to be laying around the workshop or the house.

Of course, slipjoints or Iriction folders can also be constructed bymeans of diflérent tcchnical Solutions and processes. As in our previousknifcmakingguides, we describe Stefan Steigerwald's mcthods. Someare

the same as those he uses lor tolders in general, but variations occurredwhen dealing with spccific pieces of work. Thus this volume is not mean!to be a strict manual for building a folder. It is rather meant to stimulaleand encourage the reader to try building a folding knife of his/her own.You'll find your own way of doing it through your work.

Of coursCí there liad to be the typical Steigerwald scale knife once again,and Ibr one slipjoint model, I Jamascus steel wíth just the righl dimensionswas laying on the workbench. líut there are easier ways, as pointed outby the examples.

Preparad o n 9

Finally, a remark with rcspect to work safety: in order to takcgood photosof each individual work step, wc rctraincd from the usual precautionswith rcspect to satcty. Kverybody who is about to start building a kniíeshould look up thc guidelines nccessary for safety at work. Among thcscare wearing prolective goggles and sccurcly dumping or othcrwisc fixingthc parís you are working with. This is especially thc case for workingwith power tools.

1.2 Cholee of Materials

TraditionaJ malcriáis have been used to build classic slipjoints and íriclionfolders íor a long time. 1 he blades are niostíy niade of simple carbón steels,but nowadays stainless steels like 440A, 440 H, Sandvik 12C27, or similarsteels are increasingly used. For the handles, mainly natural materials,like suitablc kinds of wood, horn, or bonos wcre used. Ot course, thereis nothing that says you can't use modern and cxpcnsive materials whcn

takingon simple knife construction. A slipjoint with powdcr mctallurgical

steci, tilaniuní liners, and handle scales made of carbón fiber has its spccialappcal. For the beginners, however, for whom this volume is focused,several factors contribute to the choice of materials:

1. Avnilabili ty: Parts like the pivot of a friction folder, the clamp, or

the handle ot plain wood can be found in a córner of your workshop.Building something from available parts can be very exciting and alsosaves nioncy.

2. Workability: Basically, every knilc can be buil l by mcans ot a file, adrill, and a bit of sandpaper. But it is easier to use a blade stecl that canbe filed and polished easily. Liners made out of nickel silver or brass arealso easier to work with com pared to steel or litan i uní.

3. Price: For somebody who has just started to work on their very ñrstknife, it doesn't make sense to do so with the most expensive materials.Apart from workability, botching a blade of Crucible Partido Metallurgy(CPM) or Damascus, liners of titanium, and handle scales of mother-of-pearl is an annoying waste of money. Timéis neverwasted, it isa periodof learning. And during this period, rather plain materials, which are

12 Preparation

The discussion about whicli kinds of steel are "best" for knives is oftenquite heated. The true answer is: there is no bcst steel. Depending on the

planned use for the knife, your own skills, and the price, you'II have todecide on a compromise. Besides, in the discussion about choosing steel,questions about ihe appropriate heat treatment and the bcst edge shapefor the planned purpose are quite often ncglected. Botli parameters haveat Icast the same cffect on the cutling ab i l i t y and the general ctfcctivenessas the choice of material.

Only by means of the proper heat treatment, optimized with respectto material and use, can the steel achieve the desired quality (hardness,

flexibility, resistance against rusting, smoothness of the edge). Heattreatment that isn't opümi/ed means gambling away the potential of thesteel. 'Ihus it is recommended to use a type of steel for which the processof heat treatment iswell-known and under control—regardlessof vvhetíieryou barden the steel yourself or send it away for hardening.

'[ he blade shapc has a decisive inlluence 011 cut t ing abil i ty and the stabilityot a blade. The edge angle determines how much forcé you need for cutting.

1 he smaller the angle, the sharper the edge and thus the less pressure you

have to apply while cutting. On the other hand, the edge has to be tunedto steel and application. A blade with a hollow grind and very thin edgewould get stuck in the material it was cutting and the edge would soonbe ruined. A blade with spherical grind, betler suited lor ibis purpose,is less suited tor pressing euts. A flal grind is more robust and easier tomanufacture, a perfectly made hollow grind requircs more experience(and more machines) with grinding. But by means of the special geometryof the hollow grind, you can achieve a fine edge even with relatively thickblades. Apart from this, the hollow grind looks really noble.

Trie heat treatment of all blades created within the framework of thisbook was contracted to a company experienced in heat treating the stcelsuscd. This also saves a lot oí time for the knifemaker. Since the blades arehardened wi lh in a vacuum furnace, almost no cinder (layer of oxides)is created in the process, which would have to be ground otfafterwards.Also, it is possible to grind and polish the blade almost to completion priorto hardening. So it is sufficient to leave just two tenths of a millimeter ofmaterial at the edge prior to heat treatment.

Preparation 13

In deciding upon blade material torourslipjointsandfrietiontolders,

besides the theory of steels,practical questions are

also of importance—thesteel should be cheap and

easy to work on with simplemeans. Since "stainless" is

always a matter of taste, wedecided upon the stainless

steel N690 made by Boehler,an Austrian m a mi tac tu re r. ' I h i s

steel provides a good compromisebetween price and capabilities, it is easy to work with and polish, and theheat treatment company is up to the task of hardentng it.

N690 can also be annealed to the hardness of a spring without anyproblems, which is advantageous because the same material can be usedfor the blade and the backspring. 'Ihis means you don't have to grindanother piece of steel to the same thickness as the blade.

Damascus steel was used for the blade and lincrs of the upscale versiónoí our slipjoint íblder.

1.2.2 Materials for Handles and Other Parts

For the other parts, we also chose malcriáis that were easy to acquire,easy to work with, and not too expensive. 1-or the Hners we used brassand nickel silver, and for the bolsters we used bronze. The rivets can bemadc of stainless steel or bronze. For the screwcd pivot, we used a toggleboíl purchased at a home improvement store.

For the handles we used whatever was lying around in the workshop atthat time: kudu horn, /.iricote wood, and bog oak (admittedly, in StefanSteigerwald's workshop lots of things are laying around). All kinds ofwoods can be used, as long as they are hard and dry enough not to warp.You have to be especially caretul with rcspect to this. Since we want to

14 Preparation

rivet our knives and not screw them together, warped or oven rupluredhandle scales can't be replaced easily. 'Ib be on the safe side, use artificialmataríais sucli as C¡-10, micarta, carbón nber, or stabili/ed wood.

Please be aware that many materials used íor making knives pose a healthrisk while working with them. 'Ihe dust of many tropical woods is toxicand can cause allergic reactions, as can the dust and fibers of compounds.

Stabilized woods sometimes contain epoxy resins, mother-of-pearlcontains arsenic, and carbón fibers accumulate in your lungs. Be sure to

use suitable brealhing masks and exhaust fans when working.

Hnally, when choosing the appropriate materials for your knife, vendorsspecializing in knitemaking supplies are usually very helptul.

l.3Tools

1.3.1 The File:The Most ImportantTool

l-'iles ditter in si/e, body shape, cut, and Ihe shape of their teeth. Rasps, incontrast to files, have separately cut teeth. If these teeth are cut (negaliverake angle) they act as scrapcrs. Milled teeth (positive rake angle) cut.

Prpparation 15

Besictes the profilc of the teeth, files differ ¡n the number and order ofthe teeth on the file body.

'ihe term "file cut" describes the complete number of teeth on the file

which were created on the tile body by stroking, cutting, or milling. In

general, the harder ibe malerial you're working with, the smoother the

file cut should be.

For softer material, including soft metal, files with cut 1 should be used.The sufficiently wide distance between the teeth assures that no materialget.s stuck and clumps up on the file. For hard materials, files with cut 2are used. On those, the so-called down-cut has an angle ot about 50°, the

up-cut crosses at an angle of about 70°. 'I he up-cut créales the actual edge,

the crossing down-cut (most times cut deeper into the file body than the

up-cut) ought to break off the shavings. Hecause of the anglc, the teeth

are set altcrnately. So score marks on the material are avoided.

GRADES OF FILE CUTS

Depending on their length, files of the same cut have different cutnumbers. Swiss-pattern files are available in se ven cuts and get

progrcssively finer as the cut number goes up. American-pattern files

are available in three cuts. The number of cuts per centimeter for Swiss-

pattern files and the corresponding American-pattern equivalents is

as follows:

Swiss-pattt-rn American-pattern Cuts perCut No. Equivalen! centimeter

00 ?

0 4.5-101 Bastard 5.3-162 SecondCut 10-25

3 SmoothCut 14-35

4 25 - 506 40-71

16 Preparation

A A A A AA A A A

AA A A AA A A A,

AA A A AA A A A

AA A A A

A A A A AA A A A

AA A A AA A A A

A A A A AA A A A

AA A A A

file body

cut

tang

1 he cut number designates the number of cuts per centimeter. The grade

of cut is a means to distinguish between the various files. Common

Swiss-pattern tiles hear the grades 00 or O (toarse files íbr wood and son

materials), cut number 1 (médium cut files), and cut numbers 2, 3, 4,and 6 (smooth cut files).

Files are available in a wide variety of shapes: rectangular, triangular,round, diamond-shaped, or semicircular. Por fíat surtaces, usually Hat or

semicircular files are used. With a mili saw file, which has a singlc-cut atthe rounded edge, we work towards the shoulder (the short, blunt part

oí the blade past the edge). We do this to achieve a rounded transition

while working 011 a ílat surface.

Preparation 17

There are other ways: the transition at the shoulder can be filed with around file as well. For the rest of the surface then a file shonld he usedthat has no cut at the sides so no rough edge will be crcated around theshoulder.

Anything but a simple tool—a wide range of files is available.

Files should be cleaned on a regular base with a file card. When shavingsare stuck between the teeth, the file is blunt.

1.3.2 Sandpaper/Abrasive Cloth

As with tools ín general, it pays not to be stingy with respect to the qualityof sandpaper or abrasive cloth. A tip: sandpaper should be kept separatedaccording to grit in folders. This way you won't have any loóse, coarsegrains on your finer sandpaper.

For sanding a plano surface we need a hard substrate (wood, metal).Ibis is especially important for working at transition points, includingthe shoulder. 'Ihis will gct you clear, well-defined corners. F'or sandingrounded arcas, around the handle, for example, we use abrasive cloth orabrasive fleece.

20 Preparation

'I he advantage oí using bronze is that there is higher stability, comparedto teflon. Theretore the blade can be adjustcd to a higher degree, themovements also stay the same over a long period of time, and they arealso more exact. In addition, bronze washers are also self-lubricating.Sheet metal tor bronze washers is available as raw material in variousthkknesses (e.g. as bearing bronzc, tin bronze, etc).

Tlie thickness of the washers depends on how tight the fit of the bladeshould be. Usually the thickness is 0.1 mm (0.003") or 0.2 mm (0.007").For a bit more space between parís, a thickness of 0.3 mm (0.011") or upto a máximum of 0.5 mm (0.019") can be used.

Washers can also be omittcd altogether. In this case, the blade movesalong the liners directly. This requires outstanding surface quality. Andbesides that, the surface of the liners should be at Icast 5 to 10 Rockwellgrades (HRC) belowthat of the blade. Liners oí platinum, steel, or non-ferrous metáis are appropriate for the job. The disadvantage of making

Bronze washers are punched from astrip wíth a special tool.

Several raw washers are roughly cutout,then chucked on the lache andturned.

Preparation 21

a knife without a washer, hesides the complicated surface treatment, arethat this lype of construction is also sensitivo to very small dusl particlesand the unevenncss of the material.

1.3.5 Vise

A vise lasts for an entire lifetime—usually. Take care that the guidanceelemcnts are more or less without play and the jaws—when closed—arelevel. During our work we use them as a hack stop to achicve a clcanedge when filing. The vise shouldn't he too lightweight either. Triehcavier the vise, the better it dampens the vibrations created while filingor polishing.

1.3.6 Drill Press

In ordcr to drill some holes, a simple drill press from a home improvementstore is sufricient. You havc to takc care that the table is perpendicular tothe drill spindle. Theadjustableelements of a press, a swivel table or swivelhead, are mostly unnecessary and do not enhancc precisión.

With respect to machines and power tools for the workshop, it is a great

idea to search for used, high-quality brand-name models. 'Ihese are much

hetter to work with than cheap tools of unknown origin.

Slipjoint Folding Knife

With slipjoiiit lolders, the open and closed hlade is hcld in place by a springundcr pressure. So slipjoirits don't have a locking mechanism like backlockfolders, which are otherwise similar in construclion and which have ahammer-like spring kecping the blade in open position. In addition toholding the blade, the backspring is also the end stop for the open blade.

The re are several ways to construct the end stop tor the blade inclosed posilion. A lot of traditional knivcs don't have any end stop atall—when closed, the blade hits the backspring. More gentle to theblade is a well-defined end stop that keeps ihe edge away from thebackspring. 'Ib achieve this, you can shape the blade and backspringin a way that, when closed, the blade foot hits the corresponding partof the backspring befo re the edge touches the back of the handle.

Another obvions possibility is to use a stop pin, i.e. a sepárate pin, lorstopping the blade. We chose this variation bccause this constructionmethod is, in the end, easier to execute. In addition to this, small errors inconstruction and assembly ot the f older are easier to correet. 'I he importantissues related to this are depicted in the images on pages 51 through 53.

2.1 Designing and Drawing aTemplate

On graph paper we draw three guide lines: the two vertical linesdetermine the handle length. In addilion, we draw the topmost partof the back, and thus determine the height of the handle and the backoí ihe blade. When this is done, we sketch the outline of the handle.

Towards the hlade, the handle receives a small guard. It prevenís one'slingers from slippingonto the edge whileworkingwith ihe knife. At thesame time, we gain more space tor ihe lang. Ihe tang will be coveredby the guard later on, so no parís will stick out when the folding knifeis closed.

SHpjoint Folding Knife 23

Decermine the handle lengch by drawing cwo lines.A third line decermines cheback of our knife. Draw che concours of che handle within these boundaries.

Draw Che guard ac che front of the handle.

ln order to determine the position of the blade pivot, we draw a lineparallel to the front end of the handle about 8 mm (0.315") fartherback. The closer to the front the pivot is drawn, the longer the blaciewill be in relation to the handle. But we stül need enough space forthe tang (locking mechanism, washers).

To have enough room for spacers and an edge inside the handle whenthe folder is closed, the center point of the pivot should be a bit belowthe center of that line. If the pivot is positioned e ven lower, the bladewon't be covered far enough when the knife is closed.

24 Slipjoint Folding Knife

Starting from the center of the pivot, we use a compass to determinethe máximum length of the blade. With a curve témplate or freehand,the desired blade contour is drawn within the boundaries markedwith the compass.

After drawing the edge we gain a first impression of our knife. Wewill see whether the draft will work in three dimensions during thenext step, making a témplate.

Determine the distancebetween the center of thepivot and the front of the

handle.

Determine the pivotheight. Place it just a bitbelow the center in orderto have enough roomfor the spring inside thehandle later on.

Draw the blade's máximum possible length.This is the same length as the distancebetween the center of the pivot and the end of the handle.

Slipjoint Folding Knife 25

Draw theshape oftheblade. A curvetémplatemakes it easier10 fitid (heright contours.

The rough sketch of our knife is finished.

Cut out the blade and handle and créate u cardboard témplate of both.Paste the blade with enough material left over for designing the tanglater on. A thumbtack is used as a p re l imina ry blade pivot.

The témplate allows us to check whether the outlines of the bladeand handle fit together. The blade should vanish inside the handleas much as possible. The blade tip has to be covered completely bythe handle. Open, as well as closed, no sharp corners should stickout anywhere.

28 SMpjoint Folding Knife

we transfer the outline of the blade onto the inside of the handletémplate. This way we can start to see the shape the backspring willhave later on.

We perform another functional test—is anything poking out,does the blade fit inside the handle, is there enough space tor thebackspring? It's easier to cut cardboard now than steel later.

Next in une is the construction oí the tang. The spring moves alongthe tangeach time the tblder isopenedor closed.'Ihepart on whichit is gliding thus has to be roundcd. With our compass we draw acircle around the center of the pivot. Since the bladt1 should ulwaysmove smoothly, the área with which the tang touches liners andwashers should be large enough. 'Ihus the radius should be as bigas possible within the boundaries of thc handle outlines.

Now draw the pocket where the spring will rest. Cióse to theroundcd edge of the handle, we mark the spot where the springends. At exactly this spot on the blade, we draw the front edge ofthe pocket.

The backspring should move freely around the blade tang. For this we first drawa circle around the blade pivot.

Süpjoint Folding Knife 29

We mark the posítíon where thespring reaches.

The line depicts the front edge of thepocket for the spring.

Now determine the height of the pocket.

'Ihereafter the height of the pocket is determincd. '1 he distance betweenthe center of the pivot and the rear wall oí the pocket is (besides thestrength of the spring) the decisive factor with respect to the forcékeeping the blade in (ípen position. The farther back this spot ispositioncd (thus a deeper pocket), the better the leverage of the spring.To have enough área for a sufficient bearing (big washers) the workingpoint of the spring (depth of the pocket) should not be too far down.

The next stcp is to draw the spring. For support we mark the positionof the blade edge of the closed folder. The spring is located betweenthis line and the back of the handle. We draw it up to the rear edgeof the tang.

30 SMpjoint Folding Knife

The points where we attach the backspring are marked—the knifcwill be riveted at thcse spots later on. Trie head oí the spring andthe ñrst of thc rivets have to be separateci by a surficient distance sothere is enough clearance for work. The distance should also not betoo small, otherwise the torque will be too high.

The springlies withín thesketched áreathat is at our

disposal inside theclosed knife.

Cut outthe pocketand mountthe bladeand handletémplate.Now drawthe spring.

-C

01t-_OJ

3U

• • F •

44 4 4 4444444444444444444444444444A A A <• • • V

444444444444444444444444444A A A A *

file

ct

The hammer-shaped end of the springreaches up to the rear end of the tang.


Mark the positions formounting the spring.

Important:the re mustbe sufficientspace betweenthe spring andthe blade ofthe knife.

1he closed blade should hit a stop pin. For this we mark the endstop. 'Iheposition should he as tar to the tront as possible to achievemáximum blade length.

Wlien the knife is open, the tang should stop at the front end ot thebackspring. Prior to transferring the outlines onto the material used forthe knife, wc should check its function once again with the témplale.

For our knife we also created a functional témplate made oí brass.Ihis brass témplate is an even be I te r sample tor checking the knile's


actions and dimensions. We used alignment pins for the stop pin,pivot, and rivets. It you want to build several models of the samedesign, brass or aluminum témplales are also helpíul.

Later the témplate for the handle is copicd onto the material usedfor thc liners—in our case, a sheet of nickel silver with a thicknessof 1.0 mm (0.039").

Draw the recess ¡n chebladc.which will restagainst the stop pin.Thepin is posicioned as farforward on the knifeas possible.Thus thecorresponding recess willnot be positioned in theblade.

Now mark the positionof the stop pin insidethe handle. Once again.check the function of thetémplate.

Nowtransfer the

outline of thehandle onto

the liners (1.0mm [0.039"]nickel silver

sheet metal).


2.2 Working on the Handle

Using a waterproof íelt pen, we transfer the handlc con ton rs ontothe material. With a center punch we mark the positions oí'the bladcpivot and rivets for the spring and stop pin.

We use a hacksaw to cut out the coarse shape. 'Ihen we use sandpaperfor a brief polish to make sure the suríaces are clean and all burrsare removed.

With a center punch, transfer the positions of the pívot, stop pin, and rivets fromthe cardboard témplate.


Roughly cut out the liners.

With sand paper (grit P240), remove burrs from the blanks.

With superglue, we thcn fix both blanks—the marked liner ontop. We always drill through both l iners at the same time to makccompletely vertical drill boles.


Glue the liners together with superglue.

Now drill with a 2.8 mm (0.1 I O") bit. With a reamer, widen the hole to 3.0 mm(0.1 18").

Now we drill the marked holes. To work accurately, drill the holeswith 0.1 mm (0.003") to 0.2 mm (0.007") less in diameter and thenuse a reamer to widen the holes to their final size. For our knite weneed 3.0 mm (0.1 18") íor the pivot and 2.0 mm (0.078") for thespacersand stop pin. While reaming, make sure the rotational speed¡s slow and the bit is well lubricated.

If necessary, the outlines are once again drawn using the témplate. Thedrill holes are used as a marker when the témplate is positioned.


Willi a file, we shape the contour. í-'or this wc clamp the liners, whichare still glued together, into the vise. With aptly shaped blocks,we sand up lo a grit of P240. To be absolutely su re the pieces staytogether properly, you can use alignment pins in addition to thesuperglue.

Once che holcs are drilled and reamed, draw the outline again.

With a file, shape che contours of the liners (still glued).

Slipjoint Folding Km'fe 37

Afcer chat we refine with sand paper For the bottom we use a rounded(P240) and a suitable sanding block. sanding block to achieve a clean radius

at the guard.

Sepárate the liners andpolish the surfaces clean

Here are liners smoothly polished up to P600.

Sepárate both liners from each other—usually they will come apartby knocking them lightly on a hard surface. Clean the liner surfacesvvith sandpaper to remove any glue residue.

Now polish both liners on all sides up togrit P600. For the área aroundthe guard, we use a rounded sanding block.


2.3 Creating the Blade

First oí all, we check to make sure the blade steel is level. If necessary,the blade surfaces are ground ílat, e.g. by gluing sandpaper onto a levelbase and moving the blank across. Exact evenness is important fordril l ing the blade pivot at the precise angle. Then the outlines of theblade are transferred onto the steel. For this we use a scribcr.

At the spot marking the blade pivot we center punch, drill, then reamthe drill hole up to the size of the blade pivot, in our case 3.0 mm(0.118").

Transfer the outline of the blade from the témplate to the steel.

Center punch the posición of the blade pivot so the drill bit doesn't wander.


At the center-punched position, drill with a diameter of 2.8 mm (0.1 10").

Then ream up to 3.0 mm (0.1 18"), making sure the bit is sufficiently lubricated.

Defining the blade shape is next. We drill a series of lióles along theniarkcd lines. With a coping saw or scroll saw, we then cut through theholes. Then we refine the shape with a coarse file. We continué witha smoother file. Leave some excess material at the base of the tang sowe can work on the contact área with the spring later.


Drill just outside the scribedlines along the contour of theblade.

Cut through the holes with a coping saw or a scroll saw.

Clamp the blank in avise. With a coarse file

{cut I or cut 2) smoothout the surface.

Slipjoint Foldrng Knife 41

During this step, we also check to makc sure the blade f i ts insidethe irame. I f the blade tip sticks out a bit—as depicted in thepiloto—or there is not enough space for the spring, we correct thisas necessary.

Check to make sure the bladefits into the frame. Correct any

protrudíng parts. Leave somematerial at the tang, for adjusting the

backspring later on.

The tang sttcks out just a bit—rnark theárea to be filed off later.

The blade tip also sticks out a bit.You can adjust this later.


In order to file the pocket for the backspring, clamp the blade in thevise. First file the bottom of the pocket. The vice jaws act as a backstop and ensures that we achieve a level área on which the spring willlater rest.

We start with the file and then continué with abrasivo cloth up toP240. In order to work on the front edge of the pocket, we repositionthe blade then file and sand as before. The length of our pocket istransferred froni the témplate to the blade.

Once the blade is adjusted, clamp it inthe vise. Use the hardened jaws of thevise as a back stop for the depth of thespring pocket.

File up to the level of the vice. In doingso, be sure not to file off or round thefront end of the pocket.

Finish the filed corners with sand paper (P240).


To mark protruding áreas, we place the blade onto one of the liners.An alignment pin serves as an auxiliary blade pivot. In our example,the shape ot the blades back doesn't fit with the handle. The blade isalso protruding a bit around the guard. We mark these áreas with afelt pen.

On the backside we transfer the shape of the spring frorn pocket tohandle and check the position of the stop pin. We mark the área wherethe blade will hit.

Here the blade concour has been filed With help from the témplate, mark theand the pocket shaped. rear edge of the pocket.

Connect the liner and blade with an alignment pin and mark the protruding áreasof the blade.


Wich che blade fixcd ín open posición, transfer the shape of the pocket onto the liner.

The hammer of the backspring reaches almost as far as the stop pin, but che hammershould not be cióse enough to rest on the stop pin when the blade is open.

With a hacksaw we first cut off the rear, protruding parí ot the tang.Afterwards, the bladc will be assembled again and moved into theposition it ought to have inside the closed knife. We niark the área wherethe spring will later rest on the tang. At the moment these marks arenot ¡dcntical to the final sizc—wc Icavc a bit of material whilc workingon this. 'Ihe final adjustments of the tang and the spring will be donelater on.


Roughly cut the blade tang to thecorrect size.

Transfer the spring position onto theclosed blade.

Draw che positions of the stop p¡n and the front end of the liners.

With file and abrasive cloth we take the blade—clamped in thevise once again—down to the marked size. Then we prepare lorgrinding the blade. With the blade open, we mark the front outlinesof the handle. A bit far ther to the front we already marked the endstop of the blade, which should not extend to the edge—for thiswe mark the position through the dr i l l hole in the l iner with theblade closed.


With the waterproof pen and the blade clamped in the vise, we markshoulder on both sides. This is the perimeter of the grinding. We don'tscribe it—if we use the pen, we are always in control of our work, andlater we won't have to remove deep grooves made by the scriber.

To determine the edge, we adjust a marking too!, a caliper gauge withscriber, or calipcr to half the thickness of the edge from both sides. Thisway you can immediately see whether you hit the center or not. Lateron we work exactly in symmetry on both sides of the blade. Tn order tosee the line of the marking tool more clearly, it is helpful to grind theedge perpendicular to that line beforehand. As an alternative, layoutdye can be used.

Parallel to the front end of the handle, mark the shoulder on both sides.


Scríbe the edge of the blade with a caliper.

Now that the edge has been scribed, you can start grinding the blade.


For grinding the blade we use files and abrasive cloth. At the edgc weleave between 0.2 mm (0.007") and 0.5 mm (0.019"). Final sharpeningof thc blade edge is only done after hardening.

To make things easier, we mount the blade to a lug that wc can clampin the vise. With the file, we then form the contours by grinding,While doing so, it is important to guide the file—and later the abrasivecloth—on top of the blade with the entire surface and not to tilt. Thuswe get a consistent and even surface. We file cautiously and withoutapplying too much pressure, otherwise the lug will come undonefrom the vice. Filing is done crosswise to achieve a clean, uniformsurface.

For grindingwe use a lug.The blade is

screwed inand the píece

of metal ontop prevents

lateralmovement.


We start with a coarse file, leaving a small área next to the shoulderunfiled. During the next step we use a finer mili saw file with roundedsides and work on the entire bladc. With the mili saw file we achievea deán curve at the shoulder.

With a coarse file, shape the bladefrom the edge.

Be careful to work on the whole áreawhile retaining the transition towardsthe shoulder.

With a rounded mili saw file, work towards the shouíder.


With a rounded sanding block we work over the whole área again.While doing so, we take care to achieve a clean transition at theshoulder. We use abrasive cloth with grits P120, P240, and thenP400. With each change of grits we change the direction of sandingas well—grit after grit is ground at an angle of 90° to the previous one.Here we should not change to a ñner grit unless the whole surfaccis uniform and without scores or grooves. Besides that, we lake careto achieve clear corners and not round the área at the shoulder ortowards the back of the blade.

For work at the shoulder, use a proper sanding block.


SPRING POCKET AND STOP PIN

With many traditional slipjoint folders, the blade can bepressed beyond the closed posítion towards and ¡nto thespring.This is bad for the blade and the backspring.A properend stop keeps the blade away from the handle back. Eitherthe end stop ¡s constructed by means of an aptly shaped tangand backspring, or an additional stop pin is used.

about 2mm

With respect to the position of the stop pin, you have to find acompromise. In our case the pin is located 2 mm (0.078") behind theblade edge.

We decide to use such a stop pin because it is easier toconstruct and manufacture. The stop pin ¡s placed in such away that it is located behind the edge for the closed bladeand is hit by the tang.

The farther away from the main pivot the pin is located, thefarther the end stop reaches into the área of the edge. Thecloser the pin is moved towards the pivot, the less space isleft for the backspring—contact área and tang have to beshorter.The leverage of the spring holding the blade in placeis also less


The length x marks the distance betweenthe center of the plvot and the stop pin.

In this design, the pin is cióse to the front;the length of x ¡s quite small.Thus the

distance between the center of the pivotand rear end of the pocket (y)

¡S si nal I, too.Because of the unfavorable

amount of leverage, thespring is not able to hold the

blade strongly enough.

Pin far to the front:The

dimensión of x is rather

small.Thus the distance

y is also small and the

leverage of the spring

¡s bad.

Here the pin is farther back and theblade pocket ís correspondingly longer.

The spring is able to transfer more forcéonto the tang and thus also holds

i the blade more strongly.

\n the blade is closed, thespring presses against therear end of the tang—the

área inside the red circle inthe drawing.At this spot, theresilience acts on retractir

and holding the blade.

The pin is farther to the back, so it

lies just within the área of the tang

when the blade is closed.Thus when

the spring pocket is longer, the distance

y is longer, too. Because of the changed

leverage, the blade is held in a better way,


The larger the área of the tang around the pivot, the more spaceis left for big washers—the larger the surface área of the washer, the morestable the knife's action.The deeper the pocket for the spring, the smallerthis área becomes.

On the other hand, with a deep pocket the córner on which the spring actsalso moves backwards (the length of y).The leverage of the spring is betterand the blade is held with more forcé.

The drafts are blown up a bit to better show how these parts interact.Theideal depth of the pocket is between the depicted extremes.

The deeper the pocket, the smaller the tang, i.e. the área which leads theblade inside the knife.The smaller this área, the more difficult it becomes tobuild an accurately moving and durable blade bearing. On the other hand,

by increasing the depth of the pocket, the length of y also mercases and theblade is held more strongly by the spring.

The construction of the stop pin and the pocket develops based on the end

position, depth of the pocket, and height of the blade. Henee it ¡s advisable

to build a mockup out of cardboard, or better yet, brass, to test the functionprior to building the actual knife.


2.4 Construction of the Backspring

Put a liner onto the raw material and roughly sketch the outlines. Forspring steel we use 1.4112. As an alternative, any steel can be used thatcan be annealed to spring hardness. The spring—which is also usedas a backspacer—should be as ihick as the blade. Cutting the bladeand spring from the same piece of raw material only requires you togrind the material down to the right thickness once.

With our knife we used washers for the blade, so the frame standsapart a bit at the front end. This in turn créales room for the springto work freely. For a construction without washers, after hardening,the spring should be ground a bit, so it doesn't touch the lincrs andrub along them.

First, we work out the área which rests on the blade pocket. Thecontour ot the blade pocket is transferred onto the spring blank. Usingthe liners that we have already drillcd, we mark the position of the stoppin as a check. The spring must not go farther than this position.

Scribe the upper outline of the backspring along the liners.

SMpjoint Folding Knife 55

With a hacksaw we roughly shape the proñle of the harnmer at theend of the spring. With ñles and abrasive cloth we start the precisiónwork. In order to work at a right angle, we clamp the spring into thevise and use the jaws as a back stop for the corners. Polish the sur faceswith abrasive cloth up to grit P400. Between each step, regularly checkthe fit of the spring insicle the pocket.

Draw the shapeof che hammeron che material.

Also mark che stop pin.The end of the backspring should not reach beyond che pin.

56 Slípjoint Folding Knife

With the hacksaw. coarsely shape the contour of the hammer.

Use a file toreflne theshape—thevise jawswork as aback stop.

Polish the área with a sanding block and sand paper (P400),


Check the fit of the spring and the length of the hammer.

File the front edge of the hammerat a right angle to the correct lengthand finish.

Rernove burrs from the corners of thehammer.

After finishing the shape of the hammer, linc up the spring and bladeand tíx the spring, blade, and liners with clamps. Now, using thepreviously drilled liner, we mark the position ot'the drill holes throughwhich our blade will later be riveted. As we did with the liners, firstdrill, then ream the holes up to the desired si/e.


Fix the blade ¡nopen position.

Fit the backspring in the blade andclamp the backspring blank, theliner, and the blade together.

Using the holes ¡n the liner. drill theholes through the spring.

While reaming the drill holes, be sureto lubricare the bit.

SHpjoint Folding Knife 59

We fasten the spring to the liner (with alignment pins, if required)and again scribe the outline. We do the coarse work with a hacksaw.Similar to the work on the blade, we trien refinc the shape with filesand abrasive cloth (up to P240).

While clamped, turnche whole knife overand scribe the outlinesof the Itner onto thespring blank.

With a hacksaw, roughly saw along the scríbed line.


Shape the outer contour of the spríng with file and sandpaper.

To work flush with the liners, the spring, blade, and Hners areassembled again with the alignment pins and clamped in the vise. Inorder to outline the inner contours, we first scribe the front, springypart of the backspring. The shape of the rear part is determined bythe position of the blade inside the closed knife. We now draw theoutline, while leaving enough room for the blade.


In the vise, finish the outer concour of the spring.

Mount theblade, springblank, andliners withalignmentpins.

With a caliper. scribc the inner The rear part of the spring mirrors thecontour of the spring parallel to the shape of the blade.top edge.


Just in íront oí the front dril l hole, the thicker, rear área narrows downto become the thin, springy front part. Wc draw this transition as asoft curve. In the front, between the hammer and the stationary partoí thespring, the thickness of the spring measures a constant 2.0 mm(O.Ü78"). Again, we dr i l l along the linc andcut through the holes witha coping saw or scroll saw. After that, we continué as usual: filing andgrinding up to P400.

Draw thetransition tothe springypart.

Drill along the markedoutline.


Wich a coping saw or scroll saw, cuc through the excess material between thedrill holes.

Refine the outline with files and sandpaper.

It is importan! to form a clean transition between the springy part andthe stationary part of the backspring. ' Ihus you avoid notch brittlenessand fatigue Iractures. To do so, we use proper semicircular files androunded sanding blocks.

Don't test the performance of the backspring at this point! Unhardened,the spring would be permanently bent.

64 Slípjoint Folding Knife

2.5 Finishing the Tang

Mount theblade to theliner with an alignment pin. In closed position,through the drill hole in the liner, we mark the position where ourstop pin rests. Clamp the bladc into the vise and shape the área witha file, round file, and sandpaper. While doing so, repeatedly checkthe required depth.

When the bladc stop fits, reniove material from the corncrs of thetang until the tang is able to move past the stop pin. As an aid, theárea can be drawn on the blade through the dril l hole of the stop pinby means of a pen.

Mark che position of che scop pin through the hole in che liner.

Shape the recess for the stop pin with Regularly check the depth of che recess.a round file.


The tang hitsthe stop pin.The excessmaterial inthis áreahas to beremoved.

Through the stop pin hole in the liner, mark the excess on the tang.

VVith tílc and sandpapcr, the corners are accordingly removed and ihetang is ground circular. During opening and closing, the backsphngglides on this surtace. 'Ihe curve should thus be uniform and polishedcleanly.


With file and sandpaper, shape the radius.

During the next work step we shape the área of the tangf which is hitby the spring in closed position. Spring and handle back ought to beflush in this position as well. For this we remove material írom thetang. Blade and spring are placed on the liner; the blade is closed upto the end stop. We litt the spring slightly and let it rest on the blade.The excess is marked on the tang.


Quality Control:The hammerprotrudes abovethe liners with theblade in closedposition.We haveto refine the tangso the hammer sitsflush.

This part of the tang has to be ground off.


Using a slight bevel, file the área bctween the recess for the stop pinand the rear part of the tang, onto which the spring presses in closedposition. The spring oughl to act on the rear edge and thus pulí theblade into the handle. Towards the stop pin, there ought to be a bitof space,

As in the previous steps, we file and grind this área up to P400. Inbetween, we repeatediy check the progress of our work, so the springwon't be located too deep later on.

Gradually we work towards achieving the right shape; the spring has tobe flush with the liners in open and closed position. Finally, we againpolish all the surfaces. For a clean finish around the blade pivot, wepolish with P4ÜO on a plañe surface.

Regularly check the position of the spring.


The excess of the spring is clear—this amount has to be taken off the tang.

On a fíat surface, polish the lateralsurfaces of the tang.

The spring is now flush with the liner.

Here the surfaces have been finished to grit P400.

70 SHpjoint Folding Knife

2.6 Precisión Work on the Blade and Spring

Polish the lateral surfaces and the back of the blade with grit P600. Forthe final polish of the blade we only work in one direction—from theblade foot to the tip. While doing so, we take care to keep well-definededges at the shoulder and towards the back.

The spring is also polished all around up to P600. To achieve therequired initial tensión, we cautiously bend the spring downwardsabout 2 mm (0.078").

Finish with P600 lengthwise on a hard and level surface.

Clamp the spring in a vise with smooth jaws and pre-bend it slightly.


Now the blade and spring can be hardened and heat-treated. The bladeis hardened to a case hardness of about 58 to 61 HRC, depending unthe steel type; the spring is hardened to around 45 HRC",.

For the spring to move smoothly along the blade, we also polish theinside up to P800.

The blade and spring are back from being hardened/annealed.

Prior to further work, cautiously polish the spring again to P800.


2.7. Intermedíate Check and Washers

After hardcning, mount the spring inside the handle and check thein i t i a l tensión. Ifnecessary, wecan cautiously bend i ta hit further. Forthe spring to move smoothly along the hlade, we polish the insidc up toP800. Thereafter the spring is once again placed inside the handle.

With a hollow punch, we stamp two washers out of teflon with athickness of 0.1 mm (0.003"). The outer diameter measures 12 mm(0.472") and fits the space on the blade tang; the inner diametermatches the pivot, which is 3.0 mm (0.118").

With the help of alignment pins, we assemble blade, spring, and stoppin. In case the blade does not move easily around the pivot after heattreatment, we cautiously widcn the drill holc with a diamond cutter(I)remel, Proxxon, etc.) or a round diamond needle file.

Assemble the spring with alignment pins for testing.The initial tensión valué is 2mm (0.078"}.


¿W

Wich two hollow punches, punch the washers out of teflon foil.


Assemble the knife to test it.

If the blade pivot is too tight, cautiously widen the drill hole with a diamond file.


Prior to the next steps we check the performance of our knife. Is theend stop alright in upen and closed position? Is the tensión of thespring surhcient? Are all the parts flush? If necessary, we touch upneccssary áreas.

The test lets you know if you've followed the process correctly so far.

76 Slipjoint Foldíng Knife

Now the blade is polished, once again, evenly along its Icngth withP600, thcn P800.

'1 he part of the tang the spring hammer movcs along is also polished asmuch as possihlc or even buffed. The smoother thc sur face, the softerthe blade movement will be when opening and closing the knite.

Rnish the tang on a fíat surface with P800. Give the surfaces of the blade a finalpolish up to P800.

The blade looks great after the final polish.

Süpjoint Folding Knife 77

2.8 Handle Scales

First oí all, we inake sure that the handle material is large and fíatcnongh to lay fíat and cover the entire suríace oí the liners. If necessary,grind the handle material Hat with sandpaper.

Then glue the l iners to thc handle material, in this case yew.

Glue the líner to the handle scale with an epoxy glue.

After the glue has set. grind the excess glue off.


previously drilled to make the boles for attaching the spring as wellas the blade pivot. Do not drill all the way through for the stop pin.

With a saw we coarsclv outlinc thc contours. With file and sandpaperup to P240 we work step by step towards the final shape ot the handlescales. File and polish the protilo lo a roundcd shape. Afterwards, thecorners at the inside of the liners are slightly rounded/trimmed.

Pivot and rivets are prepared. For this we use bronze rods of the proper

Drill theholes for therivets throughthe liners.For the stoppin. we drillapproximately2 mm (0.078")deep, whichgives us moretolerance whencutting the pinto size.

With a table saw, roughly cut the contours of the handle scale.


Then fmish che shape with a file and sandpaper.


File and sand the three-dimensional contours of the handle.

Slightly round the inner contours of the liners.


diameter and cut them into adequate pieces. To determine the rightlength, measure while holding the parts of the knife together and add1.0 mm (0.039") to 1.5 mm (0.059") in ordcr to have enough materialíor rivcting. The ends of the rods are deburred prior to assembly.

Measure the necessary length for the rivets at the handle and add 1.5 mm (0.059").


Scribe the length of the rivet on an appropriate round material.

Cut the rivets to size with a saw and remove the burrs with a file.

Everything is ready for the final assembiy.


2.9 Assembly and Finish

We put the parts of our knife together and once again check theperformance prior to riveting.

Asscmble thc parts of the knife. A drop of oil about to fall, the blademoves smoothly once and for all.

Prior to riveting, the knife is completely assembled.


While riveting with the hammer, you should not hit too hard, othcrwisethe wood around the rivet may crack. The rivet can he pressed in thevise a bit first. Ihen the rivets are clenched with the hammer on anappropriate surface. In between we check the movements of the bladeand the specifications of the handle.

With careful blows of the hammer, flatten the ends of the rivet like a mushroom.

Check the movement of the blade several times in between flattening the rivets.


After we have finished riveting the knife, we cautiously rework therivet hcads in order to match them with the handle contours. The finalfinish is done by means of smooth sandpaper.

Remove the excess material from the rivet so it is flush with the handle.

Finish the surface with a file and sandpaper (up to P600).


To protect thc wood, we rub linseed oil or hard wax onto the handlescalcs. Wc sharpcn thc bladc edge with a diamond file. Our s l ip jointfolder is now completely finished!

Rub linseed oil into the wood using a piece of cloth.

Finally, sharpen the edge of the blade with a diamond stone.


Simple and beauciful: che finished slipjoinc folder.


2. lOVariations

2.10.1 Blade Tang

With this variation, the blade tang is not shaped as a radius. Duringopening/closing, the spring hammer lies fíat on the rear of the tang.This acts as a "resting stop" halfway along the way.

Remark: With this knife, you can clearly see what can go wrong. Thestop pin was placed a bit too cióse to the front. Ihus the corners ofthe tang had to be rounded for the tang to pass by. By rounding thecorners, a few millimeters of the arca onto which the spring couldhave acted were given away. In closed position (opposite below) it isobvious that there would have been enough space to niove the stoppin farther to the back.

Knife halfway opened: here the spring rescs on the tang noticeably.


Optimization: Notice the position of the stop pin, the stopárea, the end of the edge, and the position of the hammer.

Fríctíon Folding Knife

'I he "friction" in the terní "friction íblder" refers to the friction betweenthe blade and handle of this type of knife. Friction is the only forcéholding the blade in the open and closed position.

At the front end of the handle, wc bend a ferrule around the wood.Later, the blade pivot wül be guided and riveted with this ferrule. Atthe same time, the ferrule acts as an end stop for the blade.

We forego an end stop in closed position because the blade of ourknife docsn't rest on metal but on the wood of the handle.

3.1 Desígning and Drawing aTemplate

As with the slipjoint project, first draw the design on graph papenA guideline marks the center of our knife, a second onc depicts thedesired blade length. l:irst we draw the blade tang and plot the positionof the blade pivot—again, a bit bclow the center. Now we design theblade shape up to the first guideline.

Three guidelinesmark the center,the blade length,and the heíght ofour knife.

Friction Folding Knife 93

'Ihen we place the point of a compass on the pivot and transfcr theblade length backwards—the handle must he at least this long in orderto cover the blade completely in closed position. Draw the handle;its width depends on the dimensions oí the blade. Towards the endof the handle, slope the handle downwards a bit. This way there isa bit more room for the tip of the blade and the knife will sit moresccurely in our hand.

Within theboundariesof theguidelines,draw thebladeshape.

With a compass, transfer theblade length and thus determinethe back edge of the handle.

Draw the desired handleshape—the handle gets

broader towards the end andextends slightly beyond the

radius to securelv cover theblade tip.

94 Friction Folding Knife

We transfer the drawing onto cardboard and cut out the contours;leave some excess material aroimd the tang. A thumbtack serves asthe pivot so we can check that the blade and handle fit together. Ifnecessary, we can refine the contours.

Cut out the témplate transferred onto cardboard and assemble. Cut off anyprotruding parts, e.g. excess material at the tang.


We cióse the blade far enough for the tip to he covercd by the handle.Draw the outline of the blade inside the handle. The handle niust becut this far later on.

Determine the closed posición of che blade and transfer che oucline of che edgeonto the handle.

The straight line depicts how deeply we'll have to saw ¡nto the handle later on.


3.2 Creating the Blade

Transfer the shape of the blade onto the blade material. For the frictionfolder we use N690 fíat steel with a thickness of 1.5 mm (0.059").

With a hacksaw we roughly saw the steel. Along the marked contoursof the blade we dr i l l holes, then cut through the remaining materialwithacopingsawor scroll savv. With file and sandpaper —just l iketheprocess for the slípjoint folder—we finish the contours. Leavc someexcess material at the tang; final adjustments will be done laler.

Transfer theoutline of theblade onto thesteel.

With a hacksaw, roughly saw the contour of the blade.


Drill holes along the scribed outline and cut through the holes with a coping sawor scroll saw.

As with the slipjoint folder, file the contour of the blade.


3.3 Working on the Handle

The fcrrule on the handle holds the rivet that will act as the bladepivot. We use a piece of spring steel for this. Also suitable, and perhapscasier to work with, would be a pin of brass or bron/,e. With a caliper,we scribe the desircd width—layout dye enhances the visibility ot thescribed lines.

Use the dimensions of the other parts ot the knife to determine thefemile's measurements. ' Ihe width of the ferrule should be enoughto cover the tang. The length of the metal stríp is the circumferenceof the handle (diameter times 3.14 for a spherical protile) plus a fewextra millimcters—the corners ofien can't be bcnt complcrcly and lookugly after hammering. This área is cut off later on.

Saw the fcrrule out and clamp it in a vice to rcmove burrs with a file.Here we also use the clamping jaws as a back stop to make sure thatthe corners remain parallel.

Scribe the width of the ferrule.


Coarsely saw the ferrule out, then finish in the vise.The clamping jaws act as aback stop and helps créate a fíat surface.


Place the ferrule ¡n the vice and remove burrs with a file.

Parts of the témplate, the raw blade, and ferrule.


On the wood piece for the handle, mark the área where the ferrulewill later wrap around the handle. With a wood saw, roughiy cut outthe front part of the handle.

On the handle wood, mark the área where theferrule will wrap around the handle.

Saw out the área where the ferrule will be placed.


On the front part of the handle, outline the ferrules shape. Cul outthe shape roughly with the saw, then round out the cylinder vvith afile and sandpaper until the ferrule f i t s t ightly on the handle.

To créate the cylinder shape for the handle. use the ferrule as a témplate.


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Work on the surface of the cylinder with file and sandpaper until the ferrule fitstightly.


Now wc draw the complete handle shape on the wooden handle. Markthe área where the blade rests in closed position—we have to saw thisfar into the handle trom the bottom. After that, mark the center of thehandle on the bottom of the wood. As an indication for sawing, markthe centerline and its depth on the rear end of the handle.

Transfer che handle shape onto che wood.

Measure the depch of the required cut on che témplate and transfer it to che handle.


Mark the centén of the handle. Clamp the wood in a vise along the drawn depthof the cut. Fon orientation duning sawing, we also dnaw the centén line and depthof the cut on the end of the wood.

Cut the handle along the marked Unes.

With a saw we cut the groove into the handle along the centerline andto the marked depth. The groove has to be widened just far enoughfor the blade to slip into the handle—if the blade has too much play,there worít be enough friction for the handle to hold the blade in.


Use the blade to check whether the handle groove is wide enough. If necessary,refine the slot with a broader saw blade. If the saw blades are too thin, you canuse spacers and saw along them.


Starting coarsely and then progressively using smoother files, wc shapethe prortle of the handle step hy step. With sandpaper, give the handleits tinal shape (tbr round handles, abrasivc cloth is helpíul).

With files and sandpaper, créate the handles shape.

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3.4 Grinding the Blade

With the blade clamped in the vise, we mark the shoulder on bothsides. Scribe the blade's edge from both sides.

For filing, clamp the blade tightly in the vise. Again, we file crosswiseup to about 0.1 mm (0.003") to the scribed edge. The procedure isidentical lo that of the slipjoint foldcr. Finish with sandpaper up toP400. A hard sanding block is helplul in achieving a clean córner atthe shoulder.

With the blade adjusted and clampedin the vise, mark the shoulder on bothsides.

Scribe the center of the blade fromboth sides with a caliper.

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Fix the blade on top of the vise with two clamps.

File the lateral surface of the blade.

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With the blade clamped on the vise,file the blade tip. Use light pressureto prevent the blade from movingsideways.

Towards the shoulder, use a mili sawfile.This allows you to créate thetransition to a clean córner at theshoulder.

Remove file marks with sandpaper and a sanding block. Start with grit P180. thenwork from P240 to P400.


3.5 Connecting the Ferrule with Blade andHandle

We mount the terrule onto the handle. Check the width and depth ofthe groove again and fine tune if necessary.

Push the blade into the handle until it stops at the ferrule and adjustit in open position. The pivot is placed a hit below the centén Witha calipor we take the measurement from our témplate and mark theheight of the pivot on hoth sides of the ferrule. Perpendicular to thatwe scribe the center ot the drill hole on both sides.

Mount the ferrule on che handle.

Push the blade into the handle and check that ¡t fits ¡n the groove tightly.


Scribe the herght of the pivot on both sides. For this we use layout dye, caliper,and an auxiliar/ base as a back stop for the caliper. Now we determine thecenter of the drill hole for the blade pivot.

We center punch so the drill bit doesn't wander.

Since we ha ve to dril l on a round surface, we center punch the terruleat the pivot so the drill bit doesn't wander. Cautiously we drill at themarked position through ferrule, handle, and hladc. For this, we prc-drill on each side with the knife resting on an angle. Trien place theknife blade fíat on the vise uncí drill all the way through the knile.

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Pre-drill through the sheet metal intothe wood on one side with the knifeturned at a slight angle.

Repeat on the opposite sidc of the knife.

Now drill through the entire knife with the blade lying fíat on top of the vise.

After d r i l l ing we take our knife apart and remove burrs and otherirrcgularit ies with sandpaper. The blade tang should he round toprevent eorners trom protruding trom the handle. With a curvetémplate, we draw the desired contour around the dril l hole of thepivot. Shape the tang with file and sandpaper.


Draw the curvatura of the tang wíth a curve témplate.

Using the vise, file the shape of the tang.

In order to check whether the tang fits into the handle, we temporarilyassemble the blade on the outside. The blade has to sit within thehandle deep enough during opening and closing the knife. If not, wehave to reñne.

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Mount che blade on the outside andtheck that there is enough room forthe tang inside the handle.

Assemble the knife. using a drill bit asthe blade pivot. to check the knife inclosed position.

The knife can't be closed completely.Thus we deepen the groove in the handle abit more.

l-'or this prcliminary quality control test, an appropriately si/,ed drill bitacts as the hlade pivol. With our knife, the blade tip isn t cuvered by thehandle vvhen in closed position. The groove is not deep enough—witha saw, we rerine step by step until the blade is ablc to dip deep enoughinto the handle.


The part of the handle that protrudes above the ferrule is also filedand sanded so the handle is flush with the ferrule. With sandpaperwe clean the corners of the groove. At this point the handle wood canhe sealcd. For this we use Danish Oil, which we rub into the handlewith a piece of cloth. Be cautious with products made from linseedoil: moist pieces of cloth can ignite spontaneously after a while!

File off the protruding part of the wood and sand.

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Round the inside corners of the groove Treat the handle with linseed oil.slightly.

The parts of the friction folder prior to hardening the blade.

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3.6 Assembly and Finish

Before we sharpen the edge, we take the knife to the heat treatmentcompany to be annealed. When informed about the steel type, theperson doing the heat treatment knows the required temperaturesfor hardening and annealing. In our case, the hlades were hardenedin a vacuum and annealed to 59 HRC.

Once hardened, we satín polish the surface of the blade up to gritP800. For this we also use the sanding block and only work in onedirection—from the foot of the blade to the tip.

For the pivot we use a 3.0 mni (0.118") rod of stainless steel, which vvecut to the desired length; for riveting, about 1 mm (0.039") should beleft on each side. Prior to asscmbly, rcmove burrs from both sides.

After hardening, we scrop the blade lengchwise with P800.


Determine the required length of the pivot.

Transfer the length onto the rod and add 2 mm (0.078").


Cut the pivot to size and remove burrs from che ends.

Push the pivot through. We, once again, check that the knife isfunctioning properly. If everything fits, the ferrule is riveted. Por thiswe use a proper base (anvil, stcel block) and cautiously hammer fromboth sides alternately. Tn between, regularly check the movemcnt ofthe blade. Is the blade too tight? If you cautiously break the knifein by moving the blade to and fro a bit, it should start to move a bitmore freely.


Insert the pivot and rivet it on a hard surface.


Use a hammer and the vise for riveting. Be sure not to hit the ferrule during thisprocess.

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As a final step we sharpen the edge of the blade with a diamond tile.The handle is finished with hard wax. The friction folder is now readyfor work!

Finally, sharpen the edge with adiamond file.

Seal the handle with hard wax allaround.

A timeless tool: the finished fricción folder.

Pocketknife Making for Beginners

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