I’m flatting some end grain cutting boards on my machine because it’s too cold in the garage and 4 of them can fit on my bed quite nicely at one time.
Climb milling only 1 way, 1.25mm stepdown, .55" stepover, 200" per min feedrate (you have to go fast in endgrain or you will burn).
I’ve oversized the CAM Stock so that each stroke of the facing pass starts and stops well before and after the actual cutting boards so that I’m not plunging into it with the Whiteside 1" Spoilboard Facing bit nor it is decelerating until well after it’s cleared the stock.
Yet at the end of each stoke i’m getting this odd finish that look like the grain is being pull or sucked up.
You can see it clearly here on video or in the image below.
Those end sections have the endmill on them in (comparatively) rapid succession, relative the the other sections that have longer to cool down between passes.
You mentioned going fast or burning… so, could it just be heat?
My whiteside surfacing bit does the same thing. Seems to me that once half the bit or so is no longer “loaded” that it induces some tear out. I chock it up to being something similar to planer snipe but on a much smaller scale.
edit: High router output + sudden load drop off at a high feed rate + latency in router adjusting the rpm = higher rpm for the last 3/4" of the cut. Higher router rpm and no adjustment to feed rate = lower chip load and possible tearout.
