Thursday, August 28, 2014

No, you don't need power tools to make a knife

No question, having a grinder and belt sander and drill press makes it a lot easier and faster, but it can be done without them.  So can polishing without a buffer.  So this is a quick how-to on that.

Things you WILL need
Hacksaw.  And good blades.  General rule is you want to have three teeth across the thickness of the piece, so finer teeth for thinner stock.  This is 1/8", so I'm using 32 teeth-per-inch.  24 tpi would work well, but they were out of them.
Files.  Good ones.  Get a bastard file, preferably 12" or 14".  10" will do, but get longer if you can.  A bastard is generally the coarsest, fastest-cutting file, so use it for most material removal.
File card or wire brush.  File card is a special brush just for cleaning bits of metal out of the file teeth; a stiff wire brush will work pretty well.
Vise.  You NEED a solid vise.  Doesn't have to be huge or a blacksmiths' post vise, just a good-quality one that's solidly bolted down so it won't move.
Clamps.  Something to clamp the blade to a board.  C-clamps work well.
Drill.  You can drill pin or rivet holes with a hand-crank drill; a power drill does make it faster and easier.
Abrasive paper.  Get wet/dry paper, and get good-quality stuff; it'll last longer and cut faster.

Ok, start by taking your steel

and drawing the outline of the knife you want.
In this case I'm using a full-tang style like the kitchen knives; that means the tang is the full width and length of the grip area, you drill pin or rivet holes to help lock the scales in place.  A narrow tang I'll add a picture of later, as I just realized I don't have a shot of one.

Clamp it in the vise, and start making cuts from the edge of the steel to the line you drew

Then start at the end, and start cutting those pieces off along the line.
By making each section short, you can do a pretty good job of breaking a curve down to short straight cuts.  Then do the other side.

Then cut the tang.

No pics of that, use your imagination.

I'll note that making a long cut, like along a straight line for the tang, you may have to clamp the piece so you can hold the hacksaw at a flat angle to make the full cut.

Now adjust the piece so you can start filing the sides down to the line.
 Which should give you the profile you want.
There are two ways to file.  The usual is to push the file across the piece, which works well.  For smoothing a long area you want as true(flat & straight) as possible, draw-file: hold one end of the file in each hand, place it at the far end of the piece and draw it toward you.  There's a fine series of videos of the gunsmith at Colonial Williamsburg making a rifle from scratch, and in the second, at the 3:00 mark, it shows them using files to shape the flats on the barrel this way.

Now you need to mark on the sides where you want the transition from ricasso(the area just in front of the guard or end of the cutting area) to edge, and it helps a lot if you mark the edge.  In this case using a square and a scribe* to mark lines.  Adjust the end of the ruler so it's right at the middle, lock it, and draw it along the blade, using the scribe to mark a line.
 Then go the other direction and do the same thing.  Or flip the square over. 
 By doing it on each side, if the scribe isn't EXACTLY centered, you wind up with two lines that outline the actual edge.  Which gives you lines to file to(embigginate to see them)
Now comes the hard part: cutting the bevels, the angles from the back to the edge.

Get a piece of 2x4 or something else solid, clamp it in the vise.  Solidly, you don't want it shifting.  Then clamp the blade to it, with the edge right at the edge of the wood.
 so you can file from the edge to the back of the blade.
 Most of the time, one clamp won't cut it, so either put another where it'll brace the piece so it can't move,
or drive a nail or screw into the wood so it blocks the blade from moving.  Make sure it's low enough that the file won't hit it.  Then start filing.

I was using a 10" bastard(biggest I had), and spent ten minutes to get to this point
Little difficult to see, but it has actually removed a fair amount of material
Stop every minute or so and use the brush to clean the file; it'll cut faster and getting the bits out will give a cleaner cut, too.
ADDED: I was reminded in comments of something I forgot: chalk.  Rub some chalk on the file before use, it will help keep bits from getting stuck in the teeth.

For actually shaping the blade, that's it.  Keep filing on one side until you've got it down to the line at the edge.  I'd suggest stopping just shy of the line, then draw filing to make sure the surface is flat, or if you're not worried about perfect surfaces then fairly even.  Then flip it over and do the other side.

To polish out the file marks, start with about 80-grit wet/dry paper.  Cut a strip you can wrap around the file, or a finer file if you have one, or you can use the whole sheet if you prefer: wrap it around and as a section gets dulled turn the file over and use the other side.  When it gets dull, tear that section off.

Before you start this, put the paper in water for at least half-an-hour before using it; the water will help float the bits cut off, so they don't clog the paper as fast.  And keep some water handy to dip it in occasionally so flush the filing dust off and keep water on the abrasive.

When you've got that as smooth as you wish, move up to 120-grit or so.  You can take this just as fine as you wish, but I'd suggest stopping at 180 or 220-240 since the heat-treating is still to come.

The rest is as shown in the 'doing it with power tools'(shut up) post: mark and drill the pin holes, heat-treat, then polish.  At that point you can really polish it, but for a working knife I'd suggest no finer than 320 or 400.  Remember that after heat-treating, it'll be harder to work on, so don't get discouraged if it takes longer than you'd thought.

Making the grips, same idea: use a saw to cut to shape, then use rasp and/or file to shape, then sandpaper to finish.

And that's it.


Anonymous said...

Let's see if I can remember. A flat file's edges are parallel, a mill file's edges are parallel for half of the length then slightly tapering to the end. Bastard refers to the coarseness of the cut. A safe-edge file has no teeth on the edge. Oh yeah, rub blackboard chalk into the teeth to keep it cutting clean, less carding out the chips. This helps even more with the finer cuts.

Firehand said...

Dammit, I forgot about the chalk. Need to add that

Glen Filthie said...

Good vices are hard to find these days.

I bought 2 of those new blue ones for the shop at work and the steel that goes into them is SHIT. If you are putting serious torque on the work - as we do - they won't hold.

I saw an old one at an auction and snatched it on impulse (it looks like the one in your pic and must have a million miles on it) - and the guys in the shop have all taken back all the rotten things they've said about me.

Firehand said...

Post vise, or leg vise. MADE for serious bending/twisting/hammering. New ones are horrible expensive, but they'll last forever.

That one I picked up at a flea market cheap because no mount and the female part of the screw mechanism was cracked. Put a mount together, and put a couple of heavy hose clamps on the screw, and have been using it ever since.