Surfaced Shapeoko 3 waste board

Maybe you might want this somewhere about feed and speeds Will, feel free to move if you want.
I surfaced my Shapeoko 3 waste board today with near perfect results. I uploaded a sketchup dwg to illustrate the one “problem”, a radial ridge left by the edge of the router bit on about 12 degrees (easier to see the picture).

I figure the ridge is the result of my spindle being ever so slightly tilted in 2 directions so that the outer edge digs in (could barely feel the ridge) from about 12:15 til almost 2:00. This slight imperfection with a 3/4" diameter bit hopefully won’t be visible when I cut with a 1/4" diameter bit. I don’t plan to mess it up trying to plumb the spindle perfect, I’m no machinist. So I’ll live with it. Anyways: just trying to report successful Feed and Speed data: Makita router, 3/4" straight router bit (cheap Grizzly . com router bit) with 0.1 mm DOC at 30 mm/sec. Surfacing MDF waste board type cut…


Added to the wiki:


I suspect the ridges are caused by the rotation of the endmill and the circular movement of the router resulting in an uneven-ness of pressure being applied by the cutting edge to the MDF.

I suspect that if you re-ran the pattern in the opposite direction (climb vs. conventional) you’d get the pattern mirrored on the other side.

Could be an out of tram router with a largish bit, but I see that daily on production parts from actual machine shops when they try to rush a part to us and cut too fast. I used to see the same thing on a manual Bridgeport mill if I pushed it too hard and the head on that machine was as near perfect as it could be and got checked often. Smaller bit will put the ridges closer together, as would a tiny step over, but you might try again and just slow the feed a tiny bit, sometimes it takes very little.



Your welcome Will, glad to (help?) . Thanks Dan, I thought the larger diameter bit would increase the tram error factor. but any bit in an out of tram spindle will “ridge”. I’ll slow and watch next surfacing. It’s like 1/2 the thickness of common copy paper, I’m afraid I’ll make it worse trying to plumb the spindle with my lack of machinist skills. Since I primarily cut wood and expect to sand anyways. Great teaching Dan Thanks

I’m far from being any sort of teacher, I’ve just seen a lot of irregular parts in my line of work. I would suspect also with a large cutting bit and a 1/4" collet at a high feed you could get some deflection which would obviously make the bit out of square with your work. Again, most of this is armchair engineering since I can’t actually lay hands on the machine in question, your router could very well be out of tram as well, just trying to give other possible causes. Let us know what you figure out!


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