Best results do not seem to match chip load guidance

[KT88saturate]

I have a camaster stinger 1 with a 1kw spindle. With 1/2" pine wood, I have been making .125" doc passes with 50% stepover on a 1/4" three flute bit with an OAL of 4", with about 2.5" out from the collet. I was doing 300ipm passes at 16k rpm and getting terrible surface finish, but it was on the low side of chip load. I read that you can tune the machine a bit by just hearing if the bit is screaming or not, so I lowered the RPMs and raise the feedrate until the router was much quieter. It was basically screaming before, a sound I've come to know as chatter. I ended up setting the rpms down to 6500rpm, and the feedrate at 435ipm. This seems very counter to settings I see around the internet, but the finish is much, much better and the machine is somehow much more quiet. But there's just one problem, the chipload is now .025" instead of teh .010" I was aiming for before, yet it seems to perform much better. Is .025" chipload okay? The bit does not seem to be getting very hot. The machine does not seem to care.

The mfg has only published guidance for metal, not wood even though the bit is marketed for wood as well: https://www.harveytool.com/products/tool-details-894316

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[Jim Dawson]

Whatever works best is OK. The suggested cutting parameters are just that, suggestions. A starting point to work from.

[KT88saturate]

Whatever works best is OK. The suggested cutting parameters are just that, suggestions. A starting point to work from.

Thanks Jim! Thats good news and I am surprised at the results.

[MARV]

There was a time when metal cutting bits (end mills) were supposed to have different cutting geometry then router bits intended for cutting wood. This came directly from Leitz whose cutting tools I used for years. End mills will work on wood and many people won't see the difference. But I was lead to believe that router bits required more back clearance then their metal cutting counterparts. Heat generated in the cut may tell the difference.

With regard to cutting pine; a sharp high speed steal bit may give you better results. But as Jim Dawson says, its observations and adjustments by the operator that make the difference.