Reduce chattering in red oak?

I’m still doing some testing on my own, various boards and bits, feeds, and the like…my current “test” run is a cut out coaster with some dice on the top.

In cutting out the full cut, particularly the first pass…I’m getting a lot of chatter and chipped edges. Mostly cutting cross-grain.

I’ve tried a .0945 3 flute straight to no avail.
I’ve tried a 1/8th 2 flute fishtail to no avail.

I’m using 0.028" depth per pass
28ipm feed rate in Easel.

Should I be lowering my depth per pass? Increasing/decreasing speed rate?

Trying to figure out the right way to dial this in without just continuing to cut up wood (though it very fun)…just gets expensive while “testing” :smile:

I have noticed alot of chatter in white oak and rubberwood (hevea) as well.

Am planning on doing the x axis stiffening mod soon.

Was running a piece this weekend when the rpm on the stock spindle suddenly dropped and a few short seconds later it stopped altogether. I’m glad I’ve already got a 300w Quiet cut coming.

In moving the x axis by hand i noticed about 1/64-1/32" side to side movement in the y axis rails.
I had some preinsert nuts left over as I had ordered more than I needed for building the wasteboard.
Using those and some 90 deg. angle brackets, I anchored the center of the y axis rails to the top surface of the wasteboard. Took all the movement out of the rails.

I have some 3/16" aluminum stock on the way for the x axis to reduce the amount of flex there as well.

What I think is sometimes happening when we are experiencing chatter is the rails are flexing slightly like a spring when the bit encounters harder grain, storing energy. when the bit hits the inevitable softer grain that energy is released propelling the bit forward at increased velocity until it hit harder grain again and the cycle repeats.
With the lower power spindle the bit slows down and instead of cutting the material it digs in and drives itself along or tries to go backward depending on if it’s climb cutting or not.

The key to my hypothesis is more rigidity (less flex) in the frame and more torque at the cutting edge.

I hope to have my mods done and the new spindle on by the weekend. I’ll post my findings.

I run 0.028 depth and 30 ipm using a 1/8 ball nose bit in pine. This works fine but would be a lot softer than Oak.

I would try adjusting both down a little and see how it looks.

Just my two cents :-).