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  Top » Catalog » FAQ » Knifemaker FAQ
Knifemaker FAQ
Genegrinding2.jpg

Some general information in getting started:

The blanks are ground to 220 grit and heat treated.
The air hardening and stainless steels receive a deep cryo cycle, as do O-1 blades. The other carbon steels do not.
The blades are discolored from the heat treating process, with colors ranging from a dark gold to grey/brown. These colors come off readily as the blades are finished.

Q: Are the blades ready to put a handle on?
A: No, they must be finished first.

Q: How does one finish a blade?
A: The blade needs to be hand sanded to give it a polished appearance and remove the grind lines. I find it easiest to clamp a piece of wet/dry sandpaper to a flat plate or something similar. I use the table on my bandsaw, but a thick sheet of glass or metal works fine. I donít recommend the wifeís dining room table unless you like dining alone with cold food. A piece of aluminum from a scrap yard works, too. Fold the paper in half, clamp it down, wet it and get started. WD40 or water with some baking soda mixed in work well to lube the paper.

When sanding, take long, even strokes, moving the blade back and forth on the paper. Apply additional pressure for the obstinate areas. Lap the edge of the paper over the edge of the table to get into the plunge cut on the blade.

Start with 320 grit wet/dry paper, and then go to 400, then 600 grit paper. Donít use woodworking paper, use wet/dry paper. Donít wipe the slurry that forms on the paper off. It helps with the abrasive action.

Make sure you do both the blade and ricasso (the part behind the blade and ahead of the handles) on the knife. You want the exposed areas of the blade to be polished, too.

At the bottom of this page is an excerpt from the Bob Engnath Catalog.

Q: What if I donít have a large flat space to sand on?
A: In that case, clamp the back of the blade down to a board and hand sand, as above, but with hard sanding blocks. This is much slower and the least preferred way to do it, bit it works. The board holding the blade can be clamped to anything that will hold it. Donít use a padded sanding black. It wonít sand flat and the blades are flat ground.

NEVER LEAVE A BLADE CLAMPED TO ANY SURFACE WHERE THE POINT IS EXPOSED. IF YOU ARENíT WORKING ON IT, UNCLAMP IT AND PUT IT ASIDE.

Q: What if I get cut while Iím hand sanding?
A: If you get cut, immediately apply pressure to the cut. Wash it out. If it continues to bleed, apply a compress bandage and hold it tightly over the cut. If the cut is deep or it wonít stop bleeding, continue to apply pressure and seek medical attention. Cayenne pepper sprinkled in the cut will sometimes stop the bleeding and also introduce your family to modified yodeling and potentially bad words. It will burn like crazy but cause the small vessels to constrict.

Q: Is the blade already sharp?
A: No, the blade is not sharp. The blade has to be .020-.030Ē thick at the cutting edge before heat treating. If it is too thin the edge assumes a potato chip shape along the edge. At that point it becomes a very expensive paperweight. The blade may, however, become sharp as you hand finish it. Always be wary of the point, because sharp or not, it is still pointy. I stuck the point of a dagger 2Ē into my arm once. It was not sharp but it was pointed.

Q: How do I protect the finish when I have the blade polished?
A: I use electrical tape to wrap the blade to protect it. Harbor Freight and Wal Mart both carry it for about 50 cents a roll. A piece of split hose will work almost as well. Just wrap the blade in tape, past the point and back, then cut it off, fold the tab over and stick it down. The folded tab helps get it off.

Q: How do I put the handles on?
A: In preparing the handles, first make sure the part that goes onto the tang is flat. That sounds simple, but donít assume the expensive wood you just bought is flat. Lay a piece of sandpaper, maybe 60 to 80 grit, on a flat surface and lightly move the wood in a figure 8 to get it flat.

Next, if you knife has no bolsters, clamp a piece of wood to the tang where you want it. I use vise grips. It helps to put some leather on the jaws of the vise grips to avoid damaging the wood. Drill holes all the way through using the tangís holes as a template. Mark which side that piece goes on and repeat with your other handle scale. Mark that side. Try to use numbered, not fractional drills. A 1/8Ē pin will not fit a 1/8Ē hole. They are the same size. For 1/8Ē pins, use a #30 bit. It is slightly larger than 1/8Ē, and the pins will fit just fine. A drill press is the best way to drill straight holes.

Now that the holes are drilled, pin the two handle halves together, without the blade, and shape the front of the handles. Finish the front as much as you want it to be. Once itís glued or pinned down, working on it any farther becomes a real sticky issue.

Once the front is shaped, tape up the blade almost to the place where the handle goes. This will keep epoxy off the blade. Clean the handle material, pins and tang with alcohol. Let them dry. Mix up your epoxy, and then apply it to both handle slabs. Put some on the end of a pin and push it through one handle scale. Fit that into the appropriate hole in the tang, push a little farther, and push it through the appropriate hole in the other scale. Repeat with the rest of your pins.

Once all the pins are in place, use spring or other clamps to clamp the scales to the tang. This will cause epoxy to squeeze out, probably out the front, too. Use q-tips and alcohol to clean excess epoxy from the front of the scales and blade. A note here: we all have a tendency, in the beginning, to use too much epoxy. It makes a mess and gets everywhere. Donít use more than is needed. The knife doesnít have to look like a thick peanut butter and jelly sandwich. Just put enough on to do the job and leave it at that. Set the knife aside to dry. Donít mess with it, let the epoxy cook off.

Q: What type epoxy should I use?
A: Generally the rule has been that the longer the drying time, the stronger the epoxy. I personally use 15-20 minute epoxies. I havenít had the scales come off a knife in 15 years. There was a recent thread on the Blade Forums http://www.bladeforums.com/forums/showthread.php?t=337504&highlight=adhesives and another, I believe, on Knife Netweorks.com www.knifenetwork.com about epoxies and it was really enlightening. And the epoxies I use still work fine. Make sure the surfaces are clean and free of grease. You can even roughen the tang with some 60 grit paper to get a better hold with the epoxy. If you are using horn, really clean it well because of the animal fats that may be on it.

Q: What do I do next?
A: Once the epoxy has cured, which is slower in cold weather, shape the handle with whatever tools are available. Take care not to hit files or saws against your finished blade. Keep the blade wrapped up until you are finished working. When you finish with your handles, remove the tape and finish the top and bottom of the tang and blade. Make sure your polishing matches.

Q: What do I do if I get epoxy on the blade?
A: If there is epoxy on the blade, especially near the front of the handles, use a piece of brass to scrape it off. Brass is softer than the blade so it wonít hurt your finish.

Q: How do I sharpen my knife?
A: This is a really great place to be, because it means you are almost finished. If the blade is still fairly thick at the cutting edge, you might consider having it professionally sharpened the first time. If itís not, then itís time for a whetstone. Whetstones work best when wet, so use a light oil, or even kerosene if you are very careful, and apply oil to the coarse surface of the stone.

Take a marking pen and make a line along the cutting edge. Holding the knife at what you think is an appropriate angle, take one pass, a long smooth pull, over the length of the stone, drawing the knife from ricasso to tip over the stone. Stop. Wipe off the blade. Do you still see your mark? If so, you didnít touch the edge. Adjust your angle and try again. Take a few strokes, turn the knife over and repeat.

NEVER lay the flat of the knife on the stone and drag it across. You will miss the edge and mess up your polish.

After a few passes on each side, look at the edge. If it appears that the edge is now somewhat sharp, use a medium stone and repeat as above. Then move to a fine stone. For that really fine edge, glue some leather to a paint stirring stick. Lay some 600 grit paper on the leather and strop the edge a few times. Then remove the paper and strop with the leather.

It will take some practice, but eventually you can learn to make a knife scary sharp. When you do, refer back to the part about what to do if you get cut.

Finally, there is more information on these subjects at www.engnath.com. Itís a very informative site, geared toward the new maker. The author, Bob Engnath, died some years back, but his site lives on.

Here is the excerpt from Bob Engnath's site.

HAND RUBBED FINISH

Materials needed:

Wet or dry paper in 180 or 220, 280 or 320, 400, and 600 grit. Finer grits may be added later.

Sanding block (home made)

C - Clamp or vise.

Your knife blade arrives from us with a 220 grit, belt ground finish on the major parts and it's probably spotty gray or brown. It may look awful, but that mottled color is the result of a heat treating - freezing technique to make good stainless even better.<.< First, you have to be able to hold or clamp the blade very firmly for you to be able to keep the flat parts true. If they get "rolled" at the edges, the knife usually appears to be of much poorer quality than when the flat areas are done properly. You may use a vise, or simply C - clamp the handle area to a handy length of 2" x 4" lumber.

Second, make a sanding block from 3/4" to 1" thick wood, using the pattern below. The working, contact area should only be around 3/8" to " inch wide, with the thicker part of the wood used just to make the grip more comfortable. The narrower working surface allows a better concentration of force which will make the abrasive work more efficiently. While the working surface of the sanding black is only about " wide and 4" Long, it's a good idea to put just a little belly or crown into the long dimension of the surface. Just a few thousandths, say 20 or 30, will be plenty.

The crown, or high spot in the center of the working surface of the sanding block, makes it easier to finish the center part of a large flat area and the edge radius fits the inside curve where the bevel of the blade meets the body of the knife. Be sure to use an extra hard wood or even micarta to make the sanding block to prevent getting ripples showing in the finished blade.

Soft pads or fingertips don't work for sanding on hardened steel. The idea is to have the block level things off, not to follow the small irregularities in the metal that are already there.

Knuckle clearance on the sanding block should be enough so that you can run your hand up over the blade without touching the knuckle. Saves skin!

Next, your wet or dry paper should be torn across the short length of the sheet in quarters, for minimum waste, and held on the sanding block as shown in out sketch.

When section A is dull, usually within a dozen firm strokes, move the next section into position at the bottom of the block without tearing off the used area. As sections dull, simply move over to the next fresh area so that only about " at each side of the strip is not used.

Sanding strokes should be in a straight line with firm, two - handed, down pressure. Your "off hand" supplies a lot of extra cutting pressure by riding along with the thumb atop the back of the sanding block. The first blade will take about half an hour per inch, per side, from rough to near mirror finish, full length, both sides. The next grits are faster! When I say you should sand in a straight line, I'm not saying that you have to sand lengthwise along the blade. The idea is to have all the scratches from the size grit you're using at the moment going in the same direction.

Now you can start. Begin with 180 or 220 grit, using just enough water or Cool Tool II to keep the grit clear and cutting. Avoid building up a muddy layer on the blade. Do both sides, top and bottom, with particular care in the area where the bevel joins the body. There always seem to be a few deep scratches left over, coarse grinder marks lurking there. Try to keep your strokes even and parallel. We've found that a diagonal stroke is often the best way to begin with the first grit because you can get plenty of downward pressure and have good control. ( It doesn't much matter which way you run the paper while you're sanding, diagonal, across the blade or lengthwise along the blade. The important part is to get all the marks from one grit going in the same direction so they will be easy to see when you do the next grit in another direction. Grinding marks, going in the other direction, will then be easier to see and eliminate. ) If there is a problem with grinder scratches in the plunge cut, a small, high speed grinder is really handy. They are sold in quite a variety at hobby and tool shops, and can be a great asset if used carefully. Their major problem is that they tend to dig in just a bit, producing an rippled finish.

There is no need to polish the tang of any knife when it is going to be covered with the handle. In fact, polishing the tang will reduce the strength of both the glue joints and solder when you assemble the parts.

Barry Posner has been experimenting with various machinists cutting fluids, and found that a product called COOL TOOL II, mentioned earlier in this section, gives downright remarkable results when hand polishing stainless steel. He uses it instead of water, to float away the rubbing residue and make the abrasive paper grains cut more aggressively. We found that COOL TOOL II will reduce effort and time in hand rubbing by as much as 30 per cent. Results were so impressive that we now stock COOL TOOL II. As we introduced this stuff to the local guys, virtually every one of them came back to thank us, it's that good.

Getting rid of the 220 grinding marks can also be done with a coarse stone, as we mention in detail in another section.

Finding those left over scratches from coarser grits is not so hard if you put a few lines of marker ink along the blade each time you change grits. The marker ink will stay in any old gouges and make them easy to find.

Before switching to the next finer grit, always wipe the blade clean and inspect the surface to be sure there aren't any leftover scratches from the last grit. Any "grinder tracks", which are normally scratches running across at 90 degrees to the edge or back of the blade, show up easily. If you're working with the blade clamped down, put newspaper under it and change the paper with each grit to prevent contamination. Don't be afraid to bear down firmly with both hands. Proceed on through all 4 grits. The first grit is the hardest work and uses the most paper.

Our drawings show specific directions for each grit but that's not important as long as you use each size grit at an angle different than the previous grit. If you are tempted to work all of the grits in a lengthwise motion, don't. You'll always have some deep ones left over that show up at the last polishing and ruin the whole job. You MUST change direction with each new grit.

Check the blade under florescent light. It'll reveal flaws that an ordinary bulb does not. There is a bit of a trick to seeing the actual surface of the steel and not the bright reflections. ( On the other hand, when displaying a knife, by all means, use incandescent light to flatter it.)

The rub with 600 grit is done three times, if 600 is the finest paper you intend to use. First, at a 45 degree angle, then along the length of the blade. Stop at that point, do your guard and grip work, then come back for a third and final 600 grit rub -- BUT -- use oil instead of water this time, rubbing along the length of the blade again. Be sure to run the grit full length with each stroke so you don't get little scuff marks that happen when you reverse direction in the middle of the blade. If you are going to use finer grits than the 600, you need only do the 600 grit rubbing in one direction. The last grit used should be the one run lengthwise, for the most attractive looking finish.

If each progressive grit is done correctly, you'll start to see a mirror effect at the 400 grit, and it'll show very well at the second 600. Yes, that ugly mug staring back at you from the polished steel is really you. If there's the slightest hint of left over scratches from a previous grit at this point, you have to get rid of them or they'll be there to haunt you forever. Once those are out of the way, a light buffing with white or green compound will heighten the luster -- but it is not necessary for a working type knife.

Finishing paper is now available in 1,000, 1,200, 1,500, and 2,000 grit, for a super, hand rubbed surface.

If you're working with a slightly longer blade held in a vise, try to work on to the tip as opposed to having the tip at the end of your stroke, farthest from the body and working off the tip. Most injuries in hand rubbing occur when you run over, and off the point. Your arm is already programmed to make the back stroke, and is going to do just that, even if it means ramming the thumb right into the tip. Having the point towards your body might be a bit unsettling at first, but helps a lot in keeping you from slipping off and collecting a nasty cut. Believe me, they don't have to be sharpened to cut!

Knives with a grind line part way up the blade require a bit more care than the full Vee ground styles. The two flat, parallel surfaces above the Vee grind should be treated as separate areas and sanded with extreme care to prevent the crisp junction of bevel and body from disappearing and the blade getting rounded. This also applies to types with a false edge at the tip. Although relatively small, this area should be kept crisp and well finished, adding a great deal to the quality of your finished blade. If feeling the flat is a problem, making it difficult to keep the sanding block flat on the surface, try working the strokes in a long diagonal. This gives you more surface area to contact and a far better sense of how the block is settled onto the surface of the blade. You should go over the entire blade with one grit at a time. While narrow sections of a blade are harder to keep flat, you'll quickly discover that they also are a lot faster to polish than a much wider section. There's a lot to be said for having a grind line halfway up the blade on a two inch wide bowie.

You'll learn to hate false edges after polishing one. False edges are so narrow that there is virtually no way to keep the sanding block flat on the surface. I beat this problem with a trick that I picked up for polishing those little ridges on the back of a Japanese blade.

With the blade clamped firmly, horizontal and spine up, sand along the length of the false edge with diagonal strokes, moving sideways a bit with each back and forth movement. Watch the scratches left by each stroke to be sure that you are cutting flat on the metal. Now, using the same grit, switch direction of your stroke and go over the length of the false edge again. Each time you get a nice, even set of sanding scratches from one end to the other, switch directions and do it again. This lets you work from a visual reference rather than the tactile feedback that you get from the block moving across the metal.

Blades with fancy choil designs, or filed backs are the most difficult to finish and require more patience. Your rubbing paper must be wrapped around small dowels. or "V" shaped blocks, to get into the filed cuts, and it's usually impossible to rub in different directions. Filed decorations are also somewhat rougher than the rest of the blade, since they're cut by hand and impossible to clean up on the belt grinder. Shaped stones, used in die work, adapt themselves readily to finishing small areas of a knife blade.

Missing image here

If you do not have a workbench, or want to take your knife polishing project "on the road", you might find that anchoring the blade can be a real problem. My son, Kirk, worked out a handy device that allows you to hold a blade without much regard for where you are. The gadget looks like a rather short, crude canoe paddle. The idea is to sit on the paddle part, and use a C-clamp to hold the blade to the handle part of the shape. The "paddle" doesn't have to be rounded, and could be made is several sizes to accommodate different sized blades, or even chairs.

Most laminated (Damascus) steel is not at its best if polished to a brilliant finish. When you plan on etching to bring up the pattern, very little hand rubbing is needed. Once you have worked out the grinding lines, you are essentially finished. Etching will actually wipe out 220 grit, hand rubbed, scratches.

Many acids may be used to bring up the Damascus pattern, but ferric chloride seems to be about the safest of the lot. It doesn't make your skin smoke, and only has to be rinsed off soon, not "right now". When etching with conventional acids, establish the right depth and then finish (after cleaning and neutralizing ) with diluted phosphoric acid. It will leave a finish similar to the Parkerizing treatment, with its' rust resistant properties. You might be surprised to find that the acid attacks the hard steel more vigorously than the soft. Use a solution of baking soda in water to kill the acid after you've reached the depth of etching that you were after. At this point, the steel is still extremely susceptible to rust. An oldtrick used by gunsmiths is to warm the steel and melt a little bees way right into the surface. Don't do this if you plan to blue or blacken the steel. Once the steel enchant has been neutralized, a bit of rubbing with crocus or 2,000 grit paper will brighten the softer steel left standing slightly above the harder layers.

This technique does not work with really bold striped bars with a low number of layers, like 30 to 50, especially if they are a type with layers of pure nickel laminated to steel. For those, polish as absolutely high as possible and bring up the color with either gun bluing or black oxide.

Those little, high speed grinders are handy for cleaning up small areas, but don't try to do bigger portions of the blade. They leave dimples and ripples that are hard to get out if the stone or drum isn't worked with precise cuts.

Don't leave the freshly rubbed blade in your vise when interrupted or going off to tackle something else. The metal is so clean from the rubbing process that it will rust very quickly, and that sharp point is dangerous to anyone walking by.

Add some baking soda to your rinse and lubricating water for the rubbing and you'll find that the blades will be far less likely to rust. Even stainless steel will rust very quickly when it is absolutely clean, like it is when being polished.

Camphor of gum, found at any pharmacy, will do a lot to prevent rust in an enclosed space, like a tool box or blade storage container. It comes in a cake. Just cut the glassine envelope that it's wrapped in, and it will be effective for about three months. That's calendar months, not knife makers' months. Knife makers' months are around a year long, like when he says you'll get to your order next month.

Bolsters require a more precise method of hand rubbing to keep the metal flat enough to make the near invisible joint required for a first class knife.

Missing image here

You'll need a flat plate of something hard, steel, or better yet, a good sized chunk of polished stone. You can find bargains on broken marker stones at almost any stonecutter or try a granite machinists' flat. If you don't get the one accurate to a tenth, they're relatively cheap.

Using rubber cement, glue a whole sheet of waterproof finishing paper to the stone with the abrasive side up. I recommend a grit between 220 and 400. If the stone is larger than the paper, put the paper at a corner. This face-up paper will act as a holder to keep a second, finer sheet of abrasive paper in place on top of it. You may switch the second sheet instantly to suit exactly what is needed.

With the right grit in place, laying atop the glued down sheet, add a bit of water or Cool Tool II and begin rubbing, moving the knife blade back and forth over the paper with a hearty amount of downward pressure. The water will keep the paper cutting just a few strokes longer. The blade will level itself and true up the metal as you rub, without any rocking to round the edges and spoil the bolster joint. This trick is also handy to polish the choil area of hollow ground blades or preparing areas for guards.

HEAVY DUTY SANDING BLOCK

One of our innovative customers came up with a new sanding block. He uses a eighteen inch length of square hardwood about an inch and one quarter thick, and glues his wet and dry paper right around three sides of it with spray glue. The hardwood has a rounded handle at each end. With a hand pushing at each end, you can really bear down on the block to get rid of those stubborn scratches. "Brownells', the firearms wholesaler for gunsmiths, offers a dandy sanding block in their catalog. If using this with a knife blade which already has a sharp edge, be very careful with the length of your stroke.

Below, is a variation which many find useful for sanding areas where a lot of control, two handed, is needed.

Missing image here

HOLLOW GROUND BLADES

You wouldn't think that it would be practical to hand rub a hollow ground blade, but Clint Breshears does it, and his product indicates that the technique is darned effective.

Clint made a special set of curved sanding blocks, matched to the diameter of the wheels he prefers for hollow grinding. The blocks have about half or a third of circle shaped at the top, and the rest is simply shaped in a convenient way to be clamped into the vise. The wood he used is about an inch and a half thick. He cuts the arc of each just about an eighth of an inch smaller than the actual radius, and covers the surface with one eighth inch rubber, although he says leather might work as well.

When the blade has been polished to thirty micron on the grinder, switch over to the hand rubbing block, placing a strip of the right grit shop roll face up, on the curved and padded surface of the block. Work the blade back and forth, rubbing opposite the grinder marks.

First, any errors in clean up will become apparent with just a few strokes. Swear. Polish them out and rub again. It only takes a short time to get rid of the thirty micron scratches, eliminating all traces of a machine ground finish. From there, go to a finer grit, re polish and then buff.

Having a hollow ground finish without grinder traces in the metal is an exceptional indication of quality, and very effective in making sales.

SUPER SATIN FINISH

After blade, grip, etc. are assembled and polished to the final stage, use 500 grit paper on a sharp edged sanding block to apply the satin finish. You might decide that 500 is a bit too fine and use a grit as low as 320. Experiment.

Each stroke must run the full length and be exactly aligned with previous strokes. Move the 500 grit paper so that you have a fresh spot exposed on the edge of the sanding block for each stroke. Use light pressure and stop when you have an even satin finish. Don't try it on the guard.

If you have trouble keeping the strokes parallel, try clamping some sort of guide alongside the blade so one end of your sanding block can run along it as you work.

Good Luck ,

Gene


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