Cutting 3D shapes

[jbuell]

I am curious how one would cut a three dimensional shape without cutting into the bed of the table. Say I want to cut a 4" wide board that is 48" long into a 3 dimensional slithering snake. Assuming the board is flat, when the bit cuts the curves of the snake does it cut into the bed?

If so, how does one who has a vacuum hold down deal with a bed that is constantly being cut in to and potentially reducing suction?

I do not own a Shopbot yet so you'll have to forgive my CNC naiveness.

[billp]

Jason,
One way to do this would be to make a "pod"or "puck" that served as a miniature vacuum table and went UNDER , and inside, the perimeter of the 4"by 48" board. This way you could screw the pod to the table, draw vacuum through it to hold the board down, and then when you "cut through"the board it wouldn't go into the table. I'm sure some others will have alternate suggestions...

[zeykr]

I'd probably screw a piece of scrap mdf from the bottom to my board (making sure to have laid out the screw locations to be in center of snake so as not to cut into them), spray the bottom of the mdf with shellac so that it would hold well to vac table and then let my cut go into the mdf as a sacrificial piece.