…Junkyard Wars style. In a hurry , with what I had on hand.
The task was to make an oval punch and dap set about 3.5" by 2.25"
by about 1" to 1.25" deep (I never used a ruler on this one, strictly
eyeballed it).
I like to make large punches like this in steel and the dap bottoms in
nylon, but steel is a pain without big machines (which I don’t have)
and even with a lathe an oval would be a big pain.
So…I got a soft firebrick and carved out a depression the
correct size, and put some bronze chunks into it and melted them with
a torch. After it was full offully molten bronze I put another brick
on top to flatten the future backside of my punch and let it cool.
Some rough sanding with a 60 grit, then a 220 grit belt on the
drumsander and it was real purty!. Time so far, about an hour. Then a
1" dia round steel handle was soldered on the flat side so I could
mount in in my hydraulic press.
Now, a nice piece of nylon roughed out with a rotary file in an
electric drill was ready for melt forming. I do this by heating up
the punch and pushing it into the nylon block to melt it and conform
it’s shape to the punch. This is a rather nasty affair producing very
bad fumes, and has to be repeated several times to get a good fit. Some
cleanup with handheld 60 grit and there you have it!. Total
time…maybe 2.5 hours of actual work. Beats the crap out of
lost wax or making one in steel…
Speaking of which , I did make some in steel once or twice. Started
with a 1" plate and had a oval shape blank torch cut. This I roughed
out with a cutting torch and grinded ( EEewww, that was the time the
angle grinder (ankle grinder) slipped and took a chunk out of me) to
shape . Then as already described to finish.
Plastic Steel would work fine for bottoms; nylon is easy to refurbish
by a quickie melt forming step . Polyethylene is easier to work than
nylon, but wears out a lot faster. I gotta go. Bye, Dar.