Bits breaking UGH!

I’ve broken 4 bits in the last few days. 1 time was by an off-cut hitting the bit. 1 I suspect the feed rate was too high (the recommended settings…so I slowed it down and broke another one. and the last one I’m not sure what could’ve caused it. These are all Inventable’s bits cutting 1/4 plywood; 1/8": 2 2-fluted, 2 up-cut. 3 of them broke in the collet.

What am I doing wrong?? From what I’ve read speed rates vary for different bits and materials but is there a guide I can follow? Are these bits not good?

What RPM and depth per pass?

Right off the bat, I’m wondering what your cutting depth is.

RPM I’m not sure. The Dewalt 611 router is on its highest setting.
Depth per pass was .05in.
I did more research via the forums and discovered it might be the 1/8" collet adapter. Could be that it was not machined straight. So I have already ordered a new one from Elaire.

Are the broken bits darkened?

Runout from a not true collect adapter will not help, thats for sure but I suspect your RPM/Feed rate is too high / to slow causing the but to rub vs cut.

Why? That’s like 27k RPM.

Put it on setting 1 (16k) and leave it there.


Makes sense. Learning everyday with this machine!