Inventables Community Forum

"Bone ends" during carving

Hi All,
Does anyone have any idea why when carving with 30 and 60 degree Vbits (I haven’t tested with end mills) why it’s creating these “bone ends” (see pic with circled areas in question) on the final portion of the carve? It carves everything perfectly, and then goes back around to all of those “corner” areas on the letters and does these little dots which make it look stupid vs amazing like it did before it “finalized” it. They certainly don’t preview like that! If it carved it that was as it went I’d think it was a design flaw, but as I said, it carves it perfectly then does a one more pass that screws it all up. Help! :slight_smile:

Here’s the project to troubleshoot.

Muchly appreciated


Hopefully this video link works showing the machine/software doing the weirdness.
shorturl.at/blEFX

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been looking for a solution to this problem for a while.

Makes me feel somewhat better it’s not just me :man_shrugging: :crazy_face:
Let’s see if the helpful folks here have any suggestions :slight_smile:

What endmill, specifically, are you using?
How are you setting your Z zero?
This looks like you have your Z set too low.

It does it on mine with a 90 degree v-carve bit

The typical reasons for those “dogbones” on V-carves are Z-zero set too low and deflection.

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Thanks for the reply!
Not sure I understand how my Z-zero could be set “too low?” - it’s set to the height of the wood. Deflection I can understand, any tips on how to minimize that factor?
Any help is appreciated! Thanks

I’m using the LongMill. I set my z-zero with paper on the surface of the material.

Holy Eff…Yup. I did what I know everyone has at one point or another…Was double-triple checking everything for my set up…Found the issue…I was selecting a 30° bit, but the bit is actually 20° :rage:
Entirely user error. I guess the good news is that at least I figured it out :grimacing: :stuck_out_tongue_winking_eye:
Thanks for the replies. On to carving properly now :rofl:

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Surface the workpiece and set z zero directly atop the section to be carved…don’t set z zero off at the front left when the carve area is 2ft away.

Sometime i also use this shimming technique

And I get results like this (the stars show how perfect the top is using this shim to get parallel to the gantry trick, the detail down i the pocket shows how perfect a carve can be if its surfaced on the cnc…)

Sorry for the prior reply, I hadn’t gotten to reading this comment that your all fixed now :man_facepalming::+1::+1: