Newbie Question about workpiece holding

[the great waldo]

Hi there! I'm strictly a hobbyist here and, although I'm trained in the programming of the machines, a lot of the hardware is new to me and I don't know a lot of the terminology required, so please bare with me!

Let's say for sake of argument that I want to use a small home CNC 3-axis mill to create a thickish disk from a rectangular block of wood of similar diameter. I'm assuming to mill the edges correctly I'd need to do the top half, then flip it over and do the bottom. Ignoring issues with setting datum for the cylinder for now, how would I clamp the circular half down securely so that the still-rectangular bottom half could be carved safely?

Sorry if this is a really silly question, but I've searched around for CNC specific clamps and can only find hold-down and stepper clamps, which would block tooling on the sides or parts of the sides, and I don't like the idea of trying to mill around the clamps. I'm sure some suitable equipment should exist for this but I either don't know the name or how to use it! D:

-F

I'm not sure if i'm missing something, but couldn't you just fix the block of wood to the spoil board with double sided tape and machine it. The tape usually holds well. A vacuum holder I would imagine would work but be expensive.
Cheers
Andrew

[cropwell]

I'm not sure if i'm missing something, but couldn't you just fix the block of wood to the spoil board with double sided tape and machine it. The tape usually holds well. A vacuum holder I would imagine would work but be expensive.
Cheers
Andrew

Double sided tape is OK if you have a large contact area, but the efficacy diminishes rapidly on small bits. It also doesn't do well with aggressive machining.