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feeds and speeds

Posted: Fri Aug 17, 2012 4:04 pm
by pshupe
Hello - I have just purchased a CNC Shark Pro Plus HD and teamed it with a Bosch 1617 router. I just purchased some bits, some 2 flute ballnose bits of different diameters, a few down cut spiral, and a 3/8" single flute compression bit. I am wondering if I could get some advice on speed settings for the router, speed for the cutting, in/min, and also depth per pass.

The guy at the bit place was saying that the rpms should be quite low and the feed rate be quite high. Like around 10k rpm and around 200 in/min for the larger diameter bits. He recommended 100 in/min for 1/8" bits and below. Also depth of pass should be maximum of diameter of bit.

I would like to hear from other people regarding these settings. I would hate to burn through or break these pricey bits. Thanks a lot in advance.

Cheers Peter.

Re: feeds and speeds

Posted: Fri Aug 17, 2012 4:23 pm
by tonydude
Peter,

I use my bosch variable router on the 3rd setting on most of my cuttings. On the control panel I set my feed at 80 and depth of cut no more than the dia of the bit. Rpm on router between 12000 to 15000. That goes for v carve and doing 3d work.

Tony

Re: feeds and speeds

Posted: Fri Aug 17, 2012 4:41 pm
by sk8nmike
Peter,

Feed rates and speed are almost a science in itself. There's a formula that takes in bit size, number of flutes (teeth), rpm and speed of cut (inch/feet per minute). if you want to learn more here's a place to start. http://its.fvtc.edu/MachShop3/SpeedCalc ... tecalc.htm.

My experence has been to use the rates suggested by the seller or the charts on http://precisebits.com/ and modify as needed. Depending on the material. If you're burning or melting the edges of cut you're to slow for the rpm, if the bit is screaming or flexing you're moving to fast for the rpm. You can run a 4 fluted bit at a higher rpm than a 2 fluted, but you will generate more heat. There are trade offs that you have to learn.

Re: feeds and speeds

Posted: Fri Aug 17, 2012 6:11 pm
by pshupe
Thanks Tony- I will try reducing my rpms on my router. I was at max. I only cut a few things so I'm sure I haven't done much damage yet. The guy where I got the bits said between 10k and 12k would be a good spot and very high feed rate. He was suggesting 180 for large bits and 100 for 1/8" and under. Thanks again. I have some bits and collets on order from Precise bits.

Thanks Mike - I'll check those out.

Cheers Peter.

Re: feeds and speeds

Posted: Fri Aug 17, 2012 7:34 pm
by jeb2cav

Re: feeds and speeds

Posted: Sat Aug 18, 2012 7:31 am
by pshupe
Thanks Joe - lots to learn with this stuff! Cheers Peter.