Making type stamps

[walter_davis]

I want to make some letter stamps out of UHMW plastic, to stamp into pottery clay. I need these letters to be 24pt and 72pt (there are 72 points in an inch), and that dimension isn’t necessarily the total height of a letter, as it varies by typeface.

I want to do a “typewriter” face and a grotesque (humanist sans-serif), in both upper and lower-case.

I have a Shapeoko 4 with an air-cooled spindle and HDZ, and I can cut from 7,000 to 25,000 rpm. I would be using CarbideCreate Pro and CarbideMotion to design and drive.

I’m looking for recommendations of what kind of bits to use, both for getting clean cuts in this soft, sticky material, as well as the fine details and sharp corners on type.

I have never done any V-carve cutting, so if there are any tricks to getting fine detail in the corners, while preserving as much relief as possible (so the stamp won’t “ghost” around the letters), I would appreciate all the secrets you will share.

Thanks!

[TheWoodworker (Scott Hampshire)]

If you’re working in plastic, you’ll want to look into an O flute endmill for your clearing, they are good for plastics on these kind of machines. For your V cutter, I have had great results using the 90 degree carbide insert V bit from SpeTool on Amazon. No complaints at all.