Same notches in rounded edges

Hi - Can’t seem to figure this out… Attempted to calibrate the belts and V-wheels, but still missing on the same calibration test. Do you think my belts still aren’t tight enough, or too tight? Any help is greatly appreciated.

Dimples come from lack of rigidity. You may be going too hard or something isnt optimal.
When the cutter cut its pushed in the opposite direction causing it to deflect. The dimples is due to deflection. When plunging in the bit go down only and have very little sideway deflection.


How did you set your belt tension? and are your v wheels finger tight? Do they
rotate under slight tension or do they spin freely?

I have had the same problem on all the cnc routers I’ve owned ( non industrial strength).
The Z axes all flex as the bit enters the wood. If possible, enter the wood in waste area and move to the outside. I do this by adding a line to my drawings and starting the cut there. Buy a bit ground for cnc work. They have cutting edges on the bottom. Slowing down the rate of feed helps too.

Little embarrassed to say it, but what do you mean by lacks rigidity? Belts to loose? Be heels too tight/loose? Appreciate your help!!

No hobby CNC-machine it 100% rigid, any cutter force will make the bit deviate a little. Any CNC-machine also have a component of backlash.

  • Try taking a piece of paper and attach it to the waste board (tape, whatever)
  • Put a piece of pencil in the router, lower Z enough so it make contact with the paper
  • Now take your hands and place it on the Dewalt and try to move it (axes should move)

You´ll see that the mark on the paper isnt one point, it will move about. The harder you manhandle it the larger deviation. This is lack of rigidity/backlash. Any CNC-machine will have some degree of deflection.

Belts/wheels/frame all impact rigidity, getting them tuned right will help a bit.
Also, you didnt specify what kind of carve details you used, you might have been running hard (too deep per pass, wrong bit type or mismatched feeds etc) judging by the photos.
It all play a part :slight_smile: