Rounded stars with 90degree vcarve

Hello all. I was wondering if anyone else is having or have had the problem with Vcarving stars and having some of the tips come out rounded.

I’d guess it’s just variations in your stock thickness, your wasteboard, or even clamping pressure.


Also your 90 deg bit may not actually be 90. Some of the less expensive bits are sometimes off. If some points are nice and sharp and others are not I would guess your work surface to be uneven or you have play somewhere in your system letting your v-bit move uncontrolled.

Given how evenly it progresses from nice and sharp on the bottom (Y-) to rounded on the top (Y+), and some from left (X-) to right (X+), your machine isn’t square to the wasteboard. Only takes a little difference to make a big impact. Square the machine, it does take some patience.

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This seems to be it! My back left and front right wasn’t square but now I’m having trouble having them stay in place.

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Shims are your friend. There are some various notes here on how to shim, but a little aluminum foil, shims made from soda/beer cans, etc. I bought a couple cheap feeler gauges and use material from there as shims for all sorts of things.

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I’ve been trying to shim them this afternoon. If the gap is in the back left and front right, do I shim the front left and back right?

Either, maybe both. You’re “de-parallelograming” it. Do be sure you’re using a good square to do all this.

Seems the best I can do is about 1.5mm difference. I think I can live with that for now. But I also discovered a slight dip in the waste board. I’ll have to take care of that too.

Surface the wasteboard, it’ll be square to the axis.


If you’re v-carving and set the bit too low, that can cause rounded points. If your material or the wasteboard beneath it is not leveled, it works out to be the same thing, if you zero off a low point. Since you have some stars that carved fine and others with rounded points, I’d say your material was not flat. Looks to be higher at the top of the material. Alternatively, depending on how the path was run, if the rounding got worse as you progressed from star to star, then you might have a belt or pully slipping a notch or two as you went along.

If you zero your v-bit to your material with a thin piece of wood (to give it a bit of clearance so you don’t drag the point through your material) then manually jog around your material, you should be able to see if there is a difference in height (because the piece of wood won’t fit between the material and the v-bit anymore). Then you’ll know which scenario it is.


I plan on picking up some MDF and a hand planer today. Hopefully this will fix the problem. I appreciate all the help!

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