Need your feedback with flattening

[Emmess (Matthias Solga)]

I glued an end grain cutting board, that needs to be flattened on the surface what are the end grains.

Kevin, I should have watched your " How to: Create Incredible CNC Wood Inlays" video earlier… https://www.youtube.com/watch?v=sLWLyhwLF_k ,esp.the tip to amazon things instead of DIY…

However: I now try to flatten the surface. I use the McFly cutter, trammed my surface.
0.3mm depth per pass, RPM 1000 (corrected: it is 10.000), feed rate 1200mm, plunge rate 254mm, stepover 22.5mm. The router bit appears to have sharp edges visually. Wood is Maple and Walnut

What happens though is that the machine sounds strained, as it works against hefty resistance, it produces dust instead of chips, and it also was stuck in the middle of the run, was the 2. or 3rd layer.

I now use a bowl cutter instead, much smaller surface to cut, works so far, but takes forever due to much smaller stepover.

What do I do wrong? I am really afraid that later the inlays go south because flattening is an important part of making those.

(and: the flattening tools blow the chips out below the skirt of the dust shoe, IMO due to the centifugal effect of the large diameter of the bit? At least the dust shoe device appears much less effective, when I see how nice neat and clean the shop is when I watch Kevin’s videos I always get jealous. What do I do wrong with the cleansiness? Or what do you C3D people different?)

[wmoy (Winston)]

1,000 RPM is so low your spindle shouldn’t even be turning on. And if you meant 10,000 RPM, that’s still pretty dang low. Spindles just tend to be happier/work better at higher RPMs. 16-18k should be closer to the sweet spot.

If you don’t like the size of the chips, take a shallower cut, but use a faster feed rate. That will also help avoid burning.

[mhotchin (Michael Hotchin)]

Faster feed rate, lower DOC if the machine bogs down.

For hardwoods like birch (but not end-grain) I run 10 mm stepover, 10K rpm, 2500mm/min to start, and usually end up using feedrate override to 150% or more, so feedrates of 3500mm/min and up. DOC up to about 0.75mm (about 0.03"), but could probably go deeper.

I used a smaller stepover to both reduce effects of slight tramming issues, and to avoid this bug:

Bug - Pocket toolpaths using wrong stepover

As a new discovery, this high initial step-over can cause parts of the pocket to not get machined. If the stepover is more than half the width of the bit (perhaps not the best practice, but still a valid thing to do), you can have material left behind. Since the initial stepover can be double the requested stepover, and the stepover is more than 1/2 the bit diameter, as a worst case scenario the initial stepover is more than the width of the bit. An exaggerated example - 3/4" bit, 14mm stepov…

I think that bug is fixed in the latest CC betas, but my Pro sub ran out so I haven’t upgraded past 804.

[Emmess (Matthias Solga)]

Yep! It is 10.000 RPM!

[Emmess (Matthias Solga)]

Michael, Winston: TY! I checked the cutting blades on the bit with my microscope, and boah was that dull and microchips all over the blades!
Recommendation for other readers: never judge a tools sharpness with bare eyes. I rotated the blades, and the bit makes nice chips again (of course with your recommendations applied too, DOC 0.5mm, 18k RPM, 2000mm/min.