Official Luthiers Forum!

Who is your go vendors for Cnc bits? Ive been getting quite a bit from Precise Bits, IDK, Amana and Whiteside. I'm especially looking for extend Overall length to carve necks and bodies.

_________________
https://www.instagram.com/fostinoguitars/
https://www.facebook.com/PuraVidaUkuleles/

I had an Amana .5”x6” bit for necks. The bit was up to the task, my CNC most def not. I had the clearance and travel (6” clearance and almost 12” travel) but no where near the rigidity.*

If you have a good machine (linear rails, ball screws, thick aluminum or steel plates) I’m sure any major manufacturers’ XL bits will work for wood. In fact, I often bought used bits that were too dull for aerospace but worked on maple and mahogany just fine. There was an eBay seller back in the early naughts that had really good deals on very lightly used bits, but I doubt I could identify them now.

I recommend figuring out how to carve the heel separately and key them together. Having a bit stick out 1.5” on most desktop machines is the limit. More creates too much… I’m going to say, torque arm? Something like that. In any case it tests your machine’s rigidity WAY more to just have it stick out a an extra inch, let alone having the tip out 4” to carve an acoustic neck.

*All the twelve year old boys on the forum can stop suppressing their snickers now and have yourselves a good laugh now.


Sent from my iPhone using Tapatalk Pro

Unfortunately I have a 65mm spindle so it can only do 3/8" bits but I have been thinking about upgrading to a an 80 mm spindle. I have found that the longer bits aren't as available as the 3" bits. I've also been trying to figure out a way to to carve the neck on it's side which probably isn't the best route. Now I'm on a path off carving the heel in two parts 75% with a 3" bit and possibly the balance of the heel with a longer bit. But it's not going to happen with a ER16 collet. I haven't begun to test out the deflection and or runout. I imagine it would be pretty significant.

_________________
https://www.instagram.com/fostinoguitars/
https://www.facebook.com/PuraVidaUkuleles/

There are definitely builders who CNC carve their necks on the side.
I think I would pursue that option given the limitations of your machine which you’ve mentioned so far.

Dureo do you know of any? I would love to discuss their process for clamping and other details.

_________________
https://www.instagram.com/fostinoguitars/
https://www.facebook.com/PuraVidaUkuleles/

I’m sorry I don’t know any by name but I’ve seen pictures in my internet travels, possibly on instagram.

Clearly an indexing system is needed for flipping the neck for the second side cut, such as a pin in the spoilboard at each end.

I might try a hold down method which attaches to the fretboard mating surface as that’s still flat after both cuts are finished. Maybe the super glue tape method to an aluminum angle beam.

Just thinking out loud. I haven’t needed to face this issue as I’m focused on electric necks.

I'll share an idea I have not yet tested. Repeat, NOT yet tested. It is on my list of things to try out.

I was thinking that, for most folks who are using CNC machines and are trying to carve necks, they are also using the CNC machine to make the fretboard, and using the CNC to drill indexing holes for placement of the fingerboard on the neck. They tend to be two holes, one to the left of the truss rod slot at one end, and the other to the right of the truss rod slot on the other end. If done right, those holes could be index holes for fitting the neck onto a 4 inch square, 20 inch long (or however long is needed) block securely mounted on the bed of the CNC. The neck would be on its side, indexing with holes in the side of the block. You can carve one side, then flip the neck end for end after you carve one side of the neck, and run each side as a different operation. You could index on those two holes, but also hold the neck in place with clamps placed on the headstock (carved during some other operation, while flat) with a ramp underneath, and on a piece of neck extension that you leave on until after the neck is carved. When I stack a heel, there is always a bit of a tail of neck wood that I have to cut off later; just leave that on until after carving is done. Again, if done right, you might have a little offset cleanup work to do, but not much.

If anyone tries this idea out, I would love to hear about the results!

Hi Don,

Ya I've been thinking about something along those lines as well. I want to do it with a vacuum jig to. I know even more engineering to figure out hahah. I just took a sweet Cad design course for vacuum fixtures and jigs so I think I m ight have a solution.

_________________
https://www.instagram.com/fostinoguitars/
https://www.facebook.com/PuraVidaUkuleles/