Does anyone else have issues with your bits getting pulled out of the Makita collet when carving white oak? Even if I run a 1/4" upcut bit at 70 ipm with a .1" DOC, speed set at like 4, somehow the bit get pulled right out of the collet.
I can’t think of a single time this has happened with walnut or maple, and certainly not plywood.
Just had this for the first time and in plywood. That said… I believe my feed rate was a bit aggressive thus making it both a cutter and a lever. My bit may also be a bit dull. I use they opposing wrench squeezed by one hand method to tighten my collet nut and it has never failed me until this week. Guessing the collet may need to be cleaned too
I would double check that your bit is actually .25" and not 6mm (.236"). Sometimes bits will be advertised as 1/4" but are really metric.
Also check that the collet isn’t packed with sawdust and that the collet nut is tight enough.
I haven’t done white oak but I did some red oak. .125"doc, 100ipm, 13,500rpm and no problems with the bit slipping. It was a compression bit though so probably not as much force pulling the bit down.
Defintiely not a 6 mil bit - it cut a profile just fine, then moved on to another one and BAM! got pulled out. Cleaned the collet and nut before inserting it, tightened with both wrenches.
Maybe I should just use a down cut bit in white oak, or just go incredibly slow. Even my bowl bit with get pulled out sometimes 
I just ordered an 80mm spindle from PWNCNC, so hopefully that will help alleviate my problems, too.
I wonder if maybe you have a bad collet 