Here are a couple of links that he used, and the rest of his comments so far.
http://www.hrionline.ac.uk/matshef/unwin/MSfilecutter.htmhttp://www.iarecordings.org/compilations/compilations.htmlThis got me going so over the holidays I came up with these......A filecutters hammer and chisel, and a file I made(which works very well)
Like most, I thought these things woulda taken forever by hand. But with a little insight into the process, its not that difficult. The file in the picture took approx 1.5-2 hrs including forging the blank (5160/old car spring) and heat treating for me to construct. It would be difficult to produce with any kind of profit but a fun tool to make at a demo or meeting etc. A professional filecutter apparently could go up to a couple hundred BPM and more, and at this speed my file (5/8" x 6" and 800 "teeth") would have taken roughly 5 Min. to cut including setup. Hand built wood rasps are still the rage with pro woodworkers and still there are a few people/companys in the buisiness of custom work.
About the file, the one in the pic is actually my second attempt, learned a bunch on the first try. The hammer is "key" to the process, this is probably the biggest thing the first attempt showed me. Because of the position of your body and hands, a straight handle is very painfull on the wrist. The weight of the hammer is what determines the depth of "cut", you dont swing the hammer to build inertia, almost just lift and drop. In this respect, my hammer is a little light(almost 2#), I needed to swing a bit, next hammer to be 5-8#. The first cut (the upcut) is done at about 45-50 deg., I was wandering a bit so I took a sharpie and marked lines every in. or so, this helped me a lot to straighten as I went off course. The "spacing" or indexing of the chisel is really quite easy. As you deliver a blow and make a cut, when the chisel rebounds, you slide the chisel along the surface till it registers against the "back" of the previous cut youve just made,and strike it again, and so on and so on. working from the tip to the tang in direction. In the dvd, it sounds like...at about 80 bpm or so, ticka,ticka,ticka,ticka , the ah sound being the chisel moving. I was getting about an in or so cut before I had to relocate my hand, a pro probably about double that. Once the first cut is on, you take the sharpness off with a smooth file and cut the second row (110 deg) or " the overcut". This raises a diamond shaped "tooth" that does the actual filing. The angles allow every 5-6 teeth to overlap the previous 5-6 cutting before them, this in a "double cut" file as mine. I only cut one side on my first file and when I hardened it it looked like a banana. Cutting both sides really evens out the residual stresses, as well as stress relieving before heat-treating.
The tang in a handle is pointing at your crotch. Chisel is gripped between thumb and forefinger. My chisel has a 60 deg angle of cut and it it symetrical about center, seems to index ok, but I am guessing a bit here...check out the link in the first post about the Hawley family. There are lots of pics to answer these kinds of questions. I made a 7# hammer to-day, this should help with the coarser cuts
Its seems as if I still could use a heavier hammer. The last hammer was a bear to forge for me single handed (7#), so this time I did it a little different. This one is 10#, welding an old ball pein hammer to a 2.5 x 5 piece of 4140, and then shaping a bit with an arc-air torch and grinder. Only took a couple hours this time.
Well, it didnt work very well. There was too much distance from handle to face. As I went from one hammer to another I kept on missing blows and hitting my fingers. Ive now shortened the distance a bit and matched the two. Hopefully this will make swapping easier, everything is equal except the weight
Glen
