View Full Version : Knife Build
February 06, 2008, 21:27
I'm planning on picking up a few used files from the local industrial supply store to make a knife or two. This will be my first knife build, so I'm not expecting a miracle, but it would be sweet if I could use what comes out. I'm not illiterate in the ways of basic metalworking, but I have never made something from scratch.
My ideas are to either make a rough clone of a Fairbairn-Sykes or to adapt the design of an L1A1 bayonet. The F-S should be easier due to the straight blade, but I have a bayonet to work with and that design will probably be more useful a utility and survival knife. I want to make one of these since they would hold my interest in the case of some minor disaster.
My plan is to pick up a few files, some pin stock, and a chunk of rubber if I can find it (I have other uses for this as well). I want to make the grip out of the rubber, but I have plenty of para cord in lieu of that. I could use wood, but for some reason I'm not crazy about that. I'm also toying with the idea of make low profile, flat grips.
So, my questions are as follows:
1. Does anyone have a high resolution picture of a Fairbairn-Sykes that I could use as a pattern? I will also need specific dimensions for the blade as well as the length of the grip and the size of the hilt. I will most likely use bolsters, but that remains to be seen.
2. In the event that the industrial supply store doesn't carry rubber, does anyone know where I might be able to find it? Really a thick tire would work; after all, it worked for sandals....
3. It is my impression that files do not need to be tempered since I'm sure they already are, but I just want to be sure.
4. I have read that annealing the file beforehand will make it easier to work with. Is this a good idea, and , if so, what is the best way to do so?
I think that's it for now. Any general advice or comments are certainly welcome. Just keep in mind that I'm a poor college kid. This is what I'll be doing over spring break since I'm too cheap to go anywhere.
February 07, 2008, 10:23
Your #4 & #5.
Keep in mind that a file is hardened, a bit more than an average knife.
When you are shaping your blade from the file, don't let the file get hot. Keep diping it in water as you grind the shape, and keep it cool. Too much heat can destroy the temper of the file.
It is possible to anneal and then re-temper, but this process is most likely too complex for this kind of build project. Keep it simple.
February 07, 2008, 16:03
Thanks a bunch! That should take care of the technical issues.
February 08, 2008, 19:44
Just my $.02 worth ya understand?
I think a SF style knife is not a good project to start with. If you think about it you have 4 flats, two edges, two tapers and two center lines to keep straight. I made a short version dagger once and it was harder than I would have thought.
I had two SF knives a while back and was not impressed at all. The first one snapped in two about 3" back from the tip with not great effort. The other is used as a letter opener as I never trusted them after that. A knife in the style of a Ka Bar is a far better design. IMHO. A Randall Model 14 is even better.
Rubber? Never seen rubber used as handle material, but I'm still learning.
If you need any supplies, this is a good place to find them.
February 09, 2008, 13:48
Thanks for the input and the links. I might try to adapt the L1A1 bayonet, then. This is primarily a learning project, so I don't expect perfection. The only major problem I can foresee is cutting and finishing the drop point.
As for the rubber grip, I've only seen it on my cheapo mora knife. It has a layer of rubber over the plastic grip, which actually provides a pretty good grip surface. It just seems like it would work well, although it won't look as good as wood or leather.
February 10, 2008, 07:23
As others have said, a dagger or double edge knife is not the best blade style to start with - it is like making two matching knives at once.
I would advise you to heat treat your file steel blade as a knife and not a file. Files are brittle and can snap if you use as a pry bar. Granted, knives are not pry bars either but they do get stuck in things occasionally and can break if to brittle. Also, the thinner cutting edge will be prone to chipping. The hard part here is having the patience to grind it to shape without drawing the temper. Wet grind if you can. If you see any color change from the bright steel (like blue, purple or straw) while grinding, you have started to draw the hardness out. If you can grind the blade shape without drawing the hardness, you could probably get by with heat treating it in your oven. 375 degrees for one hour and let cool. Repeat two more times and you should be all set. You can also do a differential heat treat with oxy/acet torch. Hold the bright polished blade by the tang and heat carefully along the spine and watch the temper colors as they form and head toweards the edge. When the edge is showing straw color, quick quench the blade in some warm vegetable oil. Most knife makers will heat treat while the cutting edge is still rather blunt and then use hand held sharpening stones (or a belt grinder if they are skilled) to sharpen the blade and do the final polish.
Good luck and have fun.
February 10, 2008, 11:55
Thanks! That should be a big help. Wet grinding is nor really an option, but I will keep a close eye on the steel. I have heard that motor oil works well to quench the blade, but would I be able to use this to keep the blade cool while grinding? I would have to wipe it off before I start grinding again to avoid making a huge mess.
February 10, 2008, 12:13
If you are going to grind it on a belt grinder, have a bucket of water at hand to dip it in with every pass. As you get closer to the final edge thickness, great care is required as it only takes a fraction of second to draw the hardness from the thin edge. If you do get some color in the blade while grinding, it would probably be best to finish grinding without being careful as to the color and then harden and temper when your done. I guess you could use motor oil but all the knife makers I know use vegetable oil. If you have to harden it, you need to get the whole thing hot enough (cherry red) so that a magnet will no longer stick to it and then quench it in the oil - point down.
February 10, 2008, 12:20
The paper and pencil icon says edit/delete message - I can't figure how to delete it so I am going to edit it!
February 10, 2008, 18:15
Once again, thanks a bunch! I will keep all this in mind.
Any other insight is still certainly welcomed.
June 09, 2008, 18:08
Well, it's been about four months, and I'm still not "done." I still need to finish sharpening it and then polish it, but I'm pretty sure I'm done with everything else.
I did most of the grinding on the bench grinder at home over spring break. I didn't have access to a belt grinder and there was no way I was about to buy one, which is why it looks so rough. I definately will before I try building another, but that won't be for a while.
Originally, I left the grip contour straight, since I ran out of time, and I did a cord wrap with the usual weave (I can post a link if anyone wants), but I was far from happy with that. While I was home last weekend, I took the wrap off and roughly copied the grip contour from another one of my knives using the old sharpie technique. I took it to the bench grinder for about half an hour, profiling the front of the grip and rounding the trailing end of the back. I then tried to repeat the same wrap, and I really liked the way the first layer, which is just a series of tight loops glued at the ends, felt. I tried the woven outer layer, but it didn't work well with the way the grip was now shaped. While trying to make it work, I decided to just repeat the first layer, resulting in a smooth grip, as opposed to the uneven, woven exterior.
Anyway, I'm very happy with it right now, despite the fact that it looks really rough and nasty. It realize the thickness of the blade, about 1/4", can be a drawback, but I have plenty of thinner-bladed knives, and I wanted something that can't really break. The only problem is that I couldn't find any pin stock locally, and I didn't really want to order any, so I didn't put a hilt on it. If I decide it needs one, I'll go ahead and order some pins, but I'm just going to leave it for now.
I also made a positively hideous sheath for it which I threw together in about forty-five minutes. I just wanted something to prevent it from stabbing a hole in my backpack while I was traveling back to school. Sorry, no pictures of that; it might break my new camera....
Before the cord wrapping:
Also, I compiled everyone's suggestions into notes of a sort, and I can post that too, if anyone wants to see them.
June 09, 2008, 20:44
You're handle wrapping looks good. You definately need a belt grinder for the flats. Northern Tool has a 2" X 27" for $55. The reviews are pretty mixed on them however. Grizzly has several simular small belt grinders and a $395 dollar one that a friend uses to turn out some professional looking blades that he sells at the shows.
Good luck and keep at it. I think it takes a dozen or so to get the hang of it.
You don't mention anything about annealing or heat treating in your last response. If the file is left in the hardened state that it needs to be in to work as a file, you will most likely have problems with the point breaking and your edge chipping. While a file can make a decent knife, heat treating is very important. When the blade is annealed (taken to red hot and then allowed to cool slowly in ash or sand or vermiculite) you can work or shape the metal with another file. While slower than a belt grinder, it will give you nice flat surfaces and improve the looks of your blade considerably. Get a board about as wide as your knife and clamp it with the knife on top to a workbench with the blade sticking out over the edge at 90 degrees from the edge of the bench or whatever angle is comfortable for you. Use a nice wide smooth mill bastard to smooth out the sides but stay away from the edge. The cross section of the blade should be a wedge shape. Refine the surface with finer cut files or use emory paper wrapped around a flat stick. Time consuming but the only way to do it without a belt grinder. Then do the hardening, draw out the temper and then sharpen. Your time is valuable and if you are going to take the time to make it, make it nice.
June 10, 2008, 19:50
I did heat treat it according to someone's suggestion above. I will touch it up with a belt grinder if, and probably when, I get one. I don't think I will really get the chance to work on it soon, but I'll put some more work into it when I get the chance.
Yer still a goober.
We'll play mumbly peg with it next time I'm in town.:eek: :] :beer: :confused: :cry:
June 13, 2008, 01:26
IC, if you want to learn about knifemaking, Blade forums.com is a great place to pick up the knowledge, some Makers there are among the best in the US and other parts of the world. Good luck man.:)
June 13, 2008, 14:03
Once again, thanks for all of the feedback! I'll look into that forum and see if I can pick up some knowhow. I would certainly like to keep going with this, but it might be a while before I can.
You can hand finish your blade by hand without going to a belt sander/grinder or you can use a palm sander clamped up-side down in a bench vise (with a couple of wooden blocks with cutouts for the body of the palm sander).
To use the vibratory palm sander just flip it over with the sanding side up and clamp it so that it doesn't move. Select a range of adhesive sandpapers (cheap roll self-adhesive 80 grit, 120 grit and 200 grit is the best) and start with the 80. When you have an even 80 grit finish switch to the 120 and repeat. When finished go to the 220 grit and get an even finish at that. You don't have to push hard, let the machinery do the work. If you use bare hands you won't wreck your heat threat. Just dip in water every time it gets warm enough to be uncomfortable. (wipe the water off before going back to the electric hand tool).
You can take a 2x4 and clamp it in your vice at a slightly down tilting angle and then use a clamp to clamp the knife on the 2X4 (tip towards the end nearest you). Wrap sandpaper around an old file and draw it down the blade. Repeat until you have only the 80 grit scratches. Rotate at a right angle and do the same with the 120. Rotate back to tip down and finish with 220. You can sand "up and down" or you can just draw down, doesn't really matter. Clean everything off between grits so you don't get a huge 80 grit gouge in what took your "it just took me 4 hours to get to 220 grit" finish.
BTW, if you didn't anneal your file, normalize your blade, quench and then temper you knife it will probably snap if dropped.
June 25, 2008, 19:00
Thanks! I'll try that out if I get the chance.
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