BLADE Magazine

How to Make a High-Tech Folder

by Allen Elishewitz

There are many methods to build a knife and there is no wrong way to do it. You can use anything from simple hand tools to industrial machines. The method I have chosen for readers to follow allows for a high-tech folder to be fashioned with either simple or large industrial-type machines, the latter of which are like the ones I own.

The fancy locking-liner folder that has resulted from this step-by-step instructional is completely handmade. The reason I choose to build all my knives in such a manner is because it gives me, the knifemaker, more flexibility in my production method. It also allows the knife to take on more of an individual and unique appearance.

 

Keep in mind that, due to space limitations, there are quite a few small steps that I have excluded. I will do my best to mention them but I will concentrate on the most important aspects of making a high-tech locking-liner folder.

For this project, the knife has titanium bolsters, a carbon fiber handle and a damascus blade. The locking-liner folder integrates a classical handle/bolster combination that, to build it, entails an intermediate level of difficulty. What makes the folder more complicated to build than other plain-handle knives is the introduction of the bolsters. The bolsters add just one more aspect to handle construction, and the alignment of the bolsters and handle material must be constantly maintained during the knife assembly.

Before a knifemaker begins fashioning a knife, he or she needs to select the materials from which it will be built. The blade can be damascus or plain stainless steel; the handle could be manmade or natural.

Whatever the materials are, they need to be gathered for the beginning of the project, and upon choosing the materials, the maker can mentally picture what the knife will look like. Colors, textures and patterns play a big role in the appearance of the final product.

In this case, the bolsters are .100-inch-thick titanium, the handle material is .125-inch-thick carbon fiber, the black G-10 spacer is .150-inch thick, the liners are .050-inch-thick titanium and the blade material is .125-inch-thick damascus.

I gather all my materials and put the titanium and steel on a piece of cardboard. Then I take blue layout spray and I spray them, allowing me to see what I scribe when I begin drawing patterns on them.

After the layout spray is dried, I take a vise clamp and I clamp my pattern onto the .050-inch-thick liner material. With a carbide-tip scribe, I trace the pattern of my handle onto the titanium.

For the knife, you will need two liners—one is the lock side and one is the opposite side. Then you want to scribe your bolsters. Remember you also need two bolsters, one for the left and one for the right side of the knife. You want to clamp your blade pattern onto your damascus bar and then scribe out the pattern of the blade. Continue this process for each part of the knife.

Once all your parts have been scribed, you are ready to cut them out. Remember to always wear safety glasses and hearing protection when operating a band saw. Make sure you run the band saw at the correct speed for the material you are cutting. For example, you want to run your band saw faster when you are cutting your handle material, slower when you are cutting your blade material and thicker titanium.

Depending on the tooth per inch, you might want to run a little bit faster when you are cutting thin liner materials. If you do not run the blade faster, you are chancing stripping the teeth off the blade.

When cutting, I use a push-stick to protect my fingers and allow leverage in tight areas. I also wear gloves, mainly to lessen the vibration to my hands.

All titanium liners will be placed on my lapping machine. This machine laps the surface of the titanium so it is flat. The reason why you want your liners flat is that you will get a much smoother action and prevent warping of the liners, and thus the stressing of the folder when it is put together.

In the lapping machine, I separate the liners with a Micarta square so they do not interfere with each other. A foam pad is placed on top of the liners and on top of the foam pad is a 20-pound weight. The pad helps distribute the weight evenly on the liners. As the machine rotates, three rings also rotate giving an even and random motion against an abrasive disk.

While the liners are lapping, I grind the blade to the scribed line with a 60-grit belt. Remember, again, to use proper ear, eye and lung protection.
After the blade has been profiled to the scribed line, I flatten one side on a disk.

I use the pattern to spot all the holes I will need to drill. After I am done spotting the blade, I remove the pattern and start drilling the holes to the correct sizes. I screw an aluminum rod into the drill table to protect me from any blade that could be pulled out of my hand by the drill bit.

Before heat-treating, I ream the tang area of the blade to a .2850-inch diameter, and my pivot pin is .250-inch in diameter. The reason why I ream undersize is because this is a damascus blade, and when I etch it, the acid will enlarge the pivot hole.

Once the blade has been profiled, drilled and reamed, it is ready for heat-treating. I wrap the blade in steel foil, and with a carbide scribe, I poke a small breather hole in the corner of the foil bag. If you do not do this, at high temperatures, all the oxygen will be burned out of the bag and it will create a vacuum. In a vacuum situation, the chances of warping your blade or of the bag welding itself to your blade are extremely high.

I take my handle pattern and clamp it onto the .050-inch-thick liner that I’ve chosen to be the lock side. Now I can spot the holes and drill them to the appropriate sizes. I take my .100-inch-thick bolsters to the disk grinder to de-burr and flatten them.

I take the liner from the lock side with all the holes drilled and use it as a pattern to transfer the holes to my bolsters. Then I take the other liner and clamp it onto the lock-side liner. I transfer-drill the spacer holes, the handle-screws holes and the bolsters-screws holes. I use the liner as a pattern to ensure more precise and consistent holes locations on all parts. The only holes I do not drill are the pivot pin and my two stop pins.

I take the two liners and screw them together through the spacer holes. The three screws holding the liners together will prevent them from shifting. This allows me to drill the pivot-pin hole and ream both pivot-pin holes together. Then I am able to drill the two stop pin holes. The reason why I do it this way is because the liners are in the condition they will be in when the knife is assembled. What I am doing here is removing all types of variables that could cause the pivot pin holes and the two stop pin holes to not be perfectly aligned.

 

At this point all holes are drilled, tapped, reamed and countersunk on the liners. I shift my attention to the bolsters, and I square up the back end where the handle material will come in contact with them. Then I counter bore the pivot pin hole to accept the head of my pivot pin. I locate the screw hole and drill and counter bore the screw hole on the bolsters. The bolsters can then be screwed onto the liners and everything should be aligned.

With the bolsters screwed onto the liners, I then flatten my handle material and square up the front end where it meets the bolsters. With a vise, I clamp the handle onto the liners, making sure there is no gap between the handle material and bolsters. I then transfer-drill the screw holes from the liners to the handle material. I drill and counter bore the handle material for the mounting screws.

I take my G-10 spacer, which has been ground to a specific size, and clamp it onto my handle pattern. I will drill out the holes for the screws. After this is done, all the parts have been drilled.

At this point, I screw the bolsters onto the liners, and I slip a pivot pin through the pivot holes of both the bolster and the liner. I insert a pivot spacer, which is a piece of G-10 that is the same thickness as my spacer material. This will prevent the front end of the knife from flexing when I contour the bolsters. Then I take my spacer and the other liner and screw the knife together. I do not attach the handle material because, when I profile the liners and contour the bolsters, I do not want to take the risk of burning the handle material.

With the knife handle assembled (minus the handle material), I start profiling the liners. I start with a 60-grit belt, eventually graduating to a 120-grit belt, and finally to a 400-grit belt. I use a variety of wheel sizes, like 8-inch, 3-inch and 1-inch wheels. Also, I use serrated and plain wheels. Serrated wheels are more aggressive on the material and will keep it cooler. Plain wheels are a lot smoother with less vibration. I use serrated wheels for the coarser-grit belts and smooth wheels for the finer-grit belts. Once the profile of the handle is completely ground to the shape I am looking for, I contour the bolsters on an 8-inch contact wheel. I grind the bolsters down to a 120-grit finish.

 

After the handle has been profiled and the bolsters have been contoured to a 120-grit finish, I screw the material onto the handle. Then I grind the handle material to the liners and I finish the handle material profile with a 400-grit belt. I make sure that the handle material is flush with the liners.

I contour the handle material with a 120-grit belt, which is my rough grind. My medium grind will result in a 400-grit finish. On the handle, I use a 600-grit slack belt. This will remove any kind of imperfection in the handle and give it a smooth appearance.

At this point, the profile of the knife is down to a 400-grit finish, and the handle material has been contoured to a 600-grit finish. I remove the handle material and complete the contouring of the bolsters. I will finish the bolsters with a 600-grit belt. After the locking-liner folder is completely taken apart, it is ready for detailing.

The carbon fiber handle and titanium bolsters will have slight chamfers on their outer edges. This is done with a 400-grit belt and it is to prevent the outer corners from being sharp and unpleasant in the hand.

I bead-blast the bolsters and handle with a mixture of three parts glass and one part aluminum oxide, giving the titanium and handle material a nice matt finish, and not too coarse to the point where it looks “dirty.” Next, I grind the spacer to remove the excess material. The spacer and handle screws also get a bead-blasted finish.

I gather the pivot pin, stop pins and washers and put away all the detailed parts to prevent them from getting scratched. The liners are the only things that do not get detailed at this point. I also give the inside of the liners a slight chamfer to remove any sharp corners.

Also, as the heat is drawn out from both sides, it helps prevent the blade from warping.

When the blade is cool enough to handle, I put it on a hardened, precision, flat piece of steel and hold it up to the light to see if there is any warpage or bow. I place the blade, with the side that I ground flat on the disk down, on that piece of steel. This side will let me know how much the blade has moved during heat-treating. Since, prior to heat-treating it was absolutely flat, the light will show any gaps.

If the blade has a bow, I use my arbor press to straighten it out. I remove the anvil that comes with the arbor press and replace it with a horseshoe-shaped piece of aluminum. The gap is about 2 ¾ inches wide and it lies on the base. This allows me to move the block of aluminum side to side so I can manipulate the steel as it requires.

By pressing the blade in the center of the gap, you produce a consistent curve throughout the blade. By shifting the aluminum plate off to one side, you can pinpoint a specific area to correct. Keep in mind that you have limited time to do this before the blade becomes too hard and brittle.

This is well worth mentioning—damascus steel has a much higher tendency to warp because the steel is placed under a tremendous amount of stress during the initial forging process. From my experience, when it comes to warping, twist-pattern damascus is one of the worst offenders. This is due to the nature of the process used to achieve a twist pattern.

 

After the straightening process, the blade is double tempered and then it is time to start working on it. The entire edge of the blade is refined, straightened and brought to a 400-grit finish. I profile the edge of the blade with a smooth 90-durometer, 8-inch wheel. I use a hard wheel for this process because I want the edge to be flat with minimal rolling of the corners. A softer wheel, if pressed hard enough, will roll the edge of the material.

When the edge is completely done, I flatten one side on the disk grinder. The side that I flatten is the same side I flatten prior to drilling and heat-treating. This gives me a known flat surface on the blade. It also removes any type of warp or bow to that one side.

If you do not flatten one side and there is a slight bow, when you surface grind your blade, the magnetic chuck will pull the blade flat. The result is that you will have a parallel blade but it will be bowed. So by flattening one side you will have a straight and parallel blade. If this was a plain stainless steel blade, I would surface grind the blade to a particular thickness. Since this is damascus, the surface grinding will take place later.

The best and most accurate way to scribe the cutting edge prior to grinding is with a height gage and granite plate. You want to measure your blade and subtract how thick you want your cutting edge to be. Then divide that number by two. That is how high you want to raise your gage.

 

A height gage has a carbide tip that is designed for scribing metal. Scribe along your cutting edge with the gage on both sides of the blade. The result will be two parallel lines, equally spaced down the center of the blade.

With a permanent marker, mark where your stop pin will come in contact with the blade. Then mark the face of your blade and scribe an arc where your ball detent will travel. By doing this you are giving yourself reference points not to grind into. If you do not do this and you over grind, your ball detent might fall into your bevel or you might sharpen your blade and it will cut your stop pin.

Now it is time to grind the blade. I will be using is a 60-grit belt on an 8-inch serrated wheel. The contact wheel is 90 durometers. This wheel will keep the blade cool, and since it is so hard, the grind lines will be crisp. A 60-grit belt is mainly a “hogger,” designed to rip away metal.

The type of grind I will be using on this blade is called a “compound grind.” This is a more advanced and complex blade due to the multiple grinds needed to achieve the desired look. A compound grind is two different heights of grinds that are connected together, resulting in a blade with two distinct cutting edges. One is thinner and much sharper for cutting and slashing, and the second edge is shorter and stouter for cutting harder objects or for armor piercing.

 

One of the first cultures to ever use this type of grind comes out of the Middle East. They would grind their daggers in this manner, leaving the tips stout to pierce through armor. Bud Nealy is a modern knifemaker who employs this style on a knife he calls the “Pesh-Kabz.” I have done this grind on some of my big fighters in the past but it wasn’t until a knife I collaborated on with Joel Pirela, named the “Helix,” that I used it again.

You want to hold the blade firmly in your hand with your wrist, forearm and elbow tight against your side, and plunge it straight into the contact wheel.

For the next step, I switch to a smooth 90-durometer contact wheel. I am using a 120-grit belt and this is the belt with which I do most of my work. The 120-grit belt removes all the 60-grit scratches, bringing the grind line close to where I want it to be. The thickness of the cutting edge is finally established.

When I stop using the 120-grit belt, I know that all the 60-grit scratches have been removed.

Something to keep in mind about the speed of my grinder is that I use a variable-speed, 2-horsepower DC grinder. With the 60-grit belt, I run the grinder at full speed, and while using the 120-grit belt, I reduce the grinder to 80-percent speed. This prevents the steel from getting too hot as the grit becomes finer. It also allows me to have better control of the grind so I do not overly grind the blade.

After taking the 120-grit belt to the blade, the height of the grind is close to where I want it. The grind is straighter, and the cutting edge is a lot thinner.

The next step is to complete the center grind. I use a 1-inch-wide, 8-inch-diameter, 70-durometer, smooth contact wheel. The softer wheel is more forgiving when used with finer grits. I use a 1-inch wheel for two reasons: First, it allows me to work both plunges on the left and right side of the grind; and secondly, it helps concentrate your grind into one specific area. I will be using 320- and 600-grit belts with this wheel. I split my belts so they overhang the wheel on both sides. This gives the grind a nice radius in the plunges.

 

The center grind is completed. I have stayed away from my reference points while grinding, and the two plunges exhibit nice radii. The finish on the grind is fine because after I use the 600-grit belt, I add white rouge to the belt. This helps polish the bevel and brings it to a much finer grit without removing any material.

To complete this blade, the front end, nearest the tip, needs to be ground. I repeat steps that I used for the center grind, but instead of grinding as high, I grind it much shorter. I also leave the cutting edge a little bit thicker to produce a blade with a strong tip and a robust cutting edge, all followed by a razor-fine edge for fine cuts.

After the blade is completely ground and the bevels have an extremely fine finish, I go around the edge of the blade with a Scotch-Brite wheel. This ensures that the edge of the blade has a fine finish and any deep scratches will be removed at this point.

It is now time for etching the damascus. I use muriatic acid in a preserve jar, and I set the jar on top of a piece of Micarta. The jar and Micarta are placed in a small fryer filled halfway with water and brought to a boil. The Micarta prevents the glass jar from breaking. When the water is at a boil, the blade is ready to be etched. I use a coat hanger with a plastic sleeve as a rod to suspend the blade in the acid. You must be careful when etching damascus blades using this technique; if you leave your blade in the muriatic acid too long, you will ruin it.

To neutralize the muriatic acid, I use a mixture of Windex, which has ammonia and detergent, and baking soda, as an added insurance.

 

After the acid is neutralized, I rinse the blade in water and I begin to polish it. It is easier to remove the residue of the blade before the water has dried. I use a medium felt wheel with a little bit of rouge and I go over the bevel and outer edge of the blade.

After polishing, I surface grind the blade. I surface grind the flats to remove the pattern, thus allowing the ball detent to ride on the smooth surface of the blade. It also helps enhance the appearance of the damascus.

I have converted my surface grinder to accept a 2-inch-by-72-inch belt. The 90-durometer, 6-inch serrated wheel will keep the blade cooler than a stone or a smooth wheel, and therefore will also prevent the blade from warping. To prevent rollovers (the edge of your blade will roll over due to the contact wheel pressure) with this set-up, you need a hard, 90-durometer wheel, and you must take lighter cuts. A lot of knifemakers have a tendency to want to remove too much material when using a belt.

I put the side that I ground flat, using the disk, down onto the magnetic chuck. I use a fine-pole magnetic chuck because it has better holding properties for knife blades. The blade is tilted at a 60-degree angle and the magnetic chuck is turned on. I use a 120-grit belt to remove the etched patterns on the flat of the blade. I do this to both sides, and I bring the thickness down to about .003-inch thicker than what I need.

Next I remove the blade and clean off my chuck. I replace the 120-grit belt with a 400-grit belt. I then put the blade back on the magnetic chuck, this time horizontally. This is the direction that I will be hand-rubbing the blade. Also I am able to see the 120-grit scratches being removed. With this grit, you do not want to remove more than .0015-inch at a time. This will ensure that your blade will remain absolutely flat.

With the blade perfectly flat and parallel, it is now time to cut the bevel for the lock in the tang. I use a brand-new 320-grit belt and a 90-durometer smooth wheel. This will ensure that the lock surface does not have any ripples. I adjust my tool rest to a specific height that I know will give me a 6 ½-degree-angle tang bevel. To verify this angle on the blade, I use a vernier protractor that is accurate to 5 minutes of a degree.

The blade is perfectly flat and parallel and it is time to correct the pivot pin hole. After heat-treating, bending the steel, flattening and surface grinding, the pivot hole is not perfectly perpendicular to the two sides.

I run a ¼-inch carbide reamer in the hole to recondition it. I then take a barrel lap, charge it with diamond paste and run it in the pivot hole. With the barrel lap, I am not trying to enlarge the hole too much but I am trying to produce a smoother and more concentric hole. This will enhance the action of the blade.

I take the two liners, and with a permanent marker, I mark a spot on the lock side. This is where the locking bar will come in contact with the blade. I slip a pivot pin and a stop pin through both liners. I use both liners because it will give me a little more support for the stop pin and pivot pin. I then place the blade on the pivot pin in the open position. With a shaving-sharp razor blade, I scribe a line where the lock will come in contact with the blade.

I carefully cut as close as I can in front of the scribed line. The band saw blade will come in contact with the ¼-inch hole in the liner, and since the band saw blade that I use is ¼-inch wide, the hole allows me to rotate the liner 90 degrees to complete the cut for the locking bar. The advantage of doing it this way is that you can keep your locking bar relatively parallel to the contours of the handle from one end to another.

If the locking bar is not parallel due to a straight cut, when you bend your spring, you will have thin and thick spots throughout your bar.

I split a 400-grit belt and I run it as a slack belt, enabling me to look at the liner while I clean the band saw cuts. After this is done, I grind the lock face to the scribed line. I de-bur my liner and bend the locking bar about 3/16-inch high. Now the knife is ready to be fitted.

I take the liner with the locking bar, insert a pivot pin, then I place my blade using the two washers and, finally, assemble the knife. At this point, I can open and close it to see if anything looks out of place. The two stop pin holes are exposed so I can insert pins and verify if the knife is working in both the open and closed positions.

 

Since the folder is of open-frame construction, the ball detent on the locking bar is exposed. When the blade is in the closed position, against the stop pin, I am able to locate and spot the blade where the ball detent will fall.

After I fit up the lock, and the ball detent has been spotted on the blade, I take apart the knife and bead-blast the liners. Then I anodize the titanium liners blue and engrave my name and the year on the inside of the liners. I place the completed liners with the rest of the parts already finished.
I take the blade, and with a carbide drill, I drill the ball detent hole. Next I polish the etched surfaces of the damascus one final time. This is to remove any type of scratches that might occur when fitting the lock. I clamp the blade onto a piece of steel so I can hand rub the flats. I take a flat piece of Micarta and hold wet/dry sand paper tightly against it. I then move it back and forth against the flats of the blade.

 

The final strokes are done in one direction over the complete length of the blade. The trick is not to fall off the flats into your bevel. If that happened, you would have to start all over again from polishing the bevels to sanding.

Now it is time to sharpen the blade and the knife is almost done. After the blade is sharp, I put the thumb stud in and engrave my logo. Everything is now ready to be assembled.

I gather all my parts that have been detailed and finished and assemble the knife. I examine each piece as I assemble it. Here is the finished knife!

 

I hope that you were able to gather some information from my method.


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