Hello. I am new to the CNC World and have been doing multiple test pieces. Im getting the hang of it but have a long way to go. Anyway- I have a few questions and am including a few pics. First- I made a Pledge of allegiance flag today and was not happy with the wording. I used a 60 degree v bit for the stars and wording, both stock bottom. I was happy with the stars (mostly) but the words did not come out well. Is that the best bit to use, if not what is recommended? I also included a pic of the tool speeds and feeds. The flag stock was 21x11.25
When I vcarve I generally have the cutdepth set deeper than I know it will actually go. a V bit will try to cut the full width between the bounding lines of the geometry. Advanced V carve I’ll set a specific depth but normal vcarve I let it do its thing.
If you haven’t removed this from the spoilboard yet we can likely salvage it pretty easily.
however I see they were there in the original carving. thinking about it more I think the circles are the bigger issue, either the bit or the collet aren’t true or there was a bit of dust and the bit got clamped in slightly askew.
if you put in the 60deg bit and spin the collet does it come to a sharp point or is there a wobble?
I would try again with a smaller piece of wood (and less words) so you can test out the machine in a couple minutes instead of a half hour.
Your file downloaded shows the letters (Bell MT) about 0.25inch tall and some less than 0.0625inch wide. Too small for a 60 degree bit. The v carve tool path using a 60 degree bit with those letters will not often exceed 1/32 inch in depth and is usually shallower than that. To approach success (if even possible with a 60), everything better be perfect (the bit angle, infinitely sharp tip, zero setting, wood level, firm clamps, feeds/rpms, machine ,etc). Use a 30 degree bit and/or larger letters and you will have better luck.
Cheers.
Nobody mentioned the wood species. You have to have a good hardwood for small lettering.
Change the font. Some fonts need extra kerning. (Kerning is the space between characters.) I’m always spreading lettering out so the small bits (of wood) don’t break off during carving. Your font looks like the characters are too close together.
Work out these kind of problems on scrap wood. Perhaps you already are doing that.
Did your bit break? There is no way this was made with an intact, aligned v-bit. The only thing that would cause this is insane wobble in the bit, loose belts, or a broken tip off the bit.
Ungroup your words and make the the spacing bigger between the letters would help. Try a different font that is not so wide or use a end mill instead. I use a .0394 down cut a lot. https://www.precisebits.com/products/carbidebits/downcut_2flute.asp It looks like your material is moving. I use two sided woodworker tape and screw down if possible.
