I wish I could claim total credit for the arbor press idea, but
mine’s a riff on one I saw while working for Doug Zaruba, many moons
What I did to make mine:
Remove the arbor, and put the arbor in a 4-jaw chuck on my large
metal lathe. (yeah, it really is all about the toys.) Drill down the
centerline of the arbor for about 1.5-2 inches, with a 1/2" drillbit.
Drill & tap a hole into the front face of the arbor for a setscrew
to hold the punches. (make sure the setscrew hole hits the centerline
of your borehole.)
I used a 1/2" drill for my ‘holder’ hole because I have assay office
stamps (from London) that are pretty beefy across the (square)
shank. (10mm or so.)
If you’re using more typical 1/4" round rod stamps, you can just use
a 1/4" borehole.
The setscrew doesn’t have to do much beyond just hanging onto the
punch. All the force comes from the arbor, so the holding rig
needn’t be anything fancy.
In the unlikely event you don’t have a large lathe with a 4-jaw, you
can easily rig the arbor into a tabletop drillpress to get a hole
down the center of the arbor. Remember, this is mostly about getting
a relatively small amount of force in the right spot, just once per
use. So the holding rig doesn’t have to be ultra precise. However, I
wouldn’t try this with a hand drill. If that’s all you’ve got, see if
you can pay somebody a couple of bucks to shoot the hole for you. It
should at least be axial to the arbor shaft.
I’ll get some pictures of it up on the website in the not-entirely-
distant future, but it’s pretty simple. For a base, I tend to use
whatever’s handy and about the right shape. I’ve got a block of UHMW
plastic with grooves in it for ring shanks. Everything else, I wing
based on the piece.
Hope this helps.