New MPCNC unexpected result

Hi there,
Finished building my Primo a few days ago and have been putting the machine to test. I’ve drawn the crown with success and have now installed my 65mm router and have been learning how to make inlays. I wanted to start with something simple: a 30mm star.

I don’t understand why the edges are not straight lines.

I’m using a 60 degree 1/4" V bit.
ESTLCAM tool path: 5mm depth limit, 0mm start level, 15mm Max carve width
3.18mm depth per pass, 45 degree plunge angle, 15mm/s feedrate, 3mm/s plunge rate, 5% stepover
5mm clearance plane

My pulleys look tight.
My only deviation from the build that I know of is my lead screw is 1-start (I ordered a 4-start) but I’ve adjusted the steps/mm accordingly for Z to 1600.

Any clues about what I could be doing wrong?
I appreciate support from this community. Thanks.

Based on the pattern of the errors, my best guess is that you are either getting chatter or something is loose.

Check the parts on the gantry for something like a cracked part. Check the grub screws to make sure they are holding firmly on the motor shafts. Check to make sure all the bearings are touching the tubing.

The load during the cut might also be way too high. If the bit is dull, or the depth of cut was too much, or the speeds too high, the bit might have been fighting back hard and that causes everything to get pushed around too much. You can try cutting in HD foam to remove all the load. Or on a small test like this you can reduce the speed by a huge amount, like 80% to see if that fixes it. Not as a final solution, but as a test to see how it works without the load.

Inlays are some of the most advanced projects. Progressing from cutouts, to 2.5D (like a pocket or rabbet) to carves to inlays each adds something else challenging. Still, this should have gone better. You should be able to make a better star that looks good to the eye, even if it doesn’t yet work for an inlay.


Thanks Jeff. You were right. I had a loose core clamp. Pocket looks good now. Onto figuring out how to make the male part…


We have a few topics about that. :stuck_out_tongue: For instance this one: V-Carve Inlay Using Estlcam (But Technique Can Be Used With Any CAM Software)


I think I got this… Not too bad for my first day.

Thanks again for the support and all I’ve learned from this community before making sawdust.


On your first couple cuts you made a star in lay with seems that tight?!!?! Voodoo!


I’m very impressed.


I’m standing on the shoulders of giants.
Thanks again.


Wow, very nice indeed, I have not even been brave enough to do inlay yet. (bigger part is that I do not have any contrasting items to do it with too. )

Just do your name. :stuck_out_tongue:

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