I’m regularly cutting through 3/4" birch plywood on a Shapeoko 4 XXL with stock Z-Plus Z-axis assembly and Carbide compact router.
My concern is that with my final pass at .75 doc being made with a 3/4" loc up-cut bit will suffer evacuation issues and cause excessive heat. I’d think that a 1" loc up-cut bit would allow better evacuation and airflow beyond the top of the material. Not finding many 1" loc up-cut bits out there…
I’ve been experimenting with a 1-1/8" loc up-cut bit but when pushing the feed rate I feel like 1/8" less bit would add to accuracy and less potential runout.
Is this an unnecessary concern?
Additionally, I’m finding I can run a 2-flute up-cut bit can run fine at Carbide’s preset #201 3-flute up-cut bit parameters with seemingly no issue.
What parameters for the #201 3-flute up-cut bit do you all find you can push to when cutting birch plywood (softwood)?
I don’t know how sensitive you are to cutting time, but you could do either a pocket, or two contours, so that you effectively create extra space for material to evacuate through.
for polycabonate, where evacuation is priority one, two and three, I use an “O flute” bit, but those are usually thinner so maybe can’t cope well with the violence of plywood… but if they’re inexpensive it could also be worth a try
btw another option is to investigate 8mm bits. iirc there are collets for the router for that size, and everything (including the grooves) are just a bit bigger so that might allow you to go both faster and have better evacuation and longer bits
