[Gallchobhair]

I need to start getting some bits. I am going to start with the ones I will need for plastic.
As I will be making a lot of Lithophanes. I see Some makers recommend O or 4 flute up spiral
bits. Now to my question when is it an up spiral or down spiral an up or down. A router can run
in one direction Conventional or another direction called climb. Since the flute on the bit spirals
in one direction only is it going to be up or down spiral independent of the direction of travel
of the router. Does this make any spence. LOL

Don

[mmoe]

The up or down spiral doesn't matter really for the climb vs. conventional. In my experience, routers tend to work better in conventional cuts in both plastics and wood. The geometry for plastics is different from that of wood or aluminum as well, so while up or down shear cutters will both work, the geometry of the helix may not work depending on the specific bit and the specific plastic. I haven't cut much plexi, so I can't say what would work best there, but for things like Delrin or ABS, I find a lower helix tends to work better than a high helix. The high helix bits I've tried generally gum up quite a lot more, and I imagine the same would be true for high helix bits on plexi.

[Trotline]

This thread gets missed a lot, but it's a really great intro to CNC router cutting tools. http://www.cnczone.com/forums/diy_cn...ions_uses.html

Luke