One shot to cut 1/8" acrylic - will onsrud upcut starter work

[nailzscott]

I have a request for a quick job for a simple cut (30" oval) needed asap. The acrylic is 1/8" and I do not have time to order a bit made for plastic. Will the onsrud upcut bit that came with my Shopbot starter router bit set work for this cut? What kind of router speeds and cut speed would be appropriate. Thanks

[Brady Watson]

Yes, the single spiral-O flute that is in the starter kit is perfect for cast acrylic.

Run 15,000 rpm and MS,1.2,0.7 - If you want to be conservative, cut it in 2 passes. BE SURE that you have good hold-down. Vacuum recommended.

-B

[gabepari]

For 1/8" I don't use spiral bits, they tend to lift the parts off the vacuum table. I use a simple 2 flute straight cut 3/16" bit (solid carbide). I run 3ips at 15K rpm, single pass, climb cut. Works for me.

[knight_toolworks]

yes lifting is an issue with thin plastic. using some spray adhesive will help. cutting at .5ips will rally help keep the part in place with some spray.

[nailzscott]

OK, thanks for the input. I will be cutting it over the weekend, so I am hoping things go well.

[majohnson]

I would think you would be better with a down cut bit. There would be much less chance of things moving during the cutting.

[nailzscott]

Complete work (46"x24" oval) with the onsrud upcut bit that came with my starter set. I experimented with the straight fluted bit, but since it was a single carbide flute, the edge was a bit jagged. It might have worked if I slowed way down. I think the down cut bit might have been a problem since the chips tended to ball up at the cut - even with the upcut. Thanks for your help.

[knight_toolworks]

downcut is an issue in plastic. you can get a lot of welding and a non smooth edge. though this depends on the quality of the plastic too.