universal neck machine

[ihavenofish]

so, ive been working on various guitar projects, and one of the biggest issues ive had in general is that every time you alter a design, you often have to remake your jigs. in addition you have to swap them out every time you want to mill a different design, then youve also got multiple for each design - front, back, fretboard, headstock, etc.

having a special jig for each operation is ok if you are making 1000 of the same item, but if you want to make custom guitars as most small builders do, you need to be able to slap on a block of wood and have the machine cut it without lost time screwing around with jigs.

make sense? no? ok, good... haha.

this is my solution:


this is a universal neck jig for a dedicated neck making cnc machine.. the central tube is a rotary axis. each side has a vacuum fixture. each fixture is the same in the image, but ultimately will be one for the back of the neck, one for the front, one for the rough wood squaring, and one for the fretboard. the neck angle is adjustable by cnc and it has inserts for headstock shapes. basically it can accomodate almost any neck, from a telecatser to a 9 string multi scale neck through.

the machine it goes on has a travelling column with about 50" travel in the X, and a swiveling spindle, making the setup 5 axis.

the rotary axis moves in the Y, which lets it move the fretboard to a belt sander to radius fretboards. fret slots are cut with a saw on the swivel axis.

combined with some clever software that takes the custom order and compiles the gcode automatically, it basically allows every neck to be completely different yet still have most of the economies of high volume fixtured production.

so any thoughts?

[woodman08]

I also thought of using the rotary axis,if you were planning on doing a few similar necks this would work fine.

[luthier]

Why send the neck to a sander to arch the fretboard when you can do it right with the cnc with a roundnose bit? I would think this would be more do-able with one rotating neck instead of 4 unless you are planning on setting up a factory..:-).

[ihavenofish]

Originally Posted by luthier Why send the neck to a sander to arch the fretboard when you can do it right with the cnc with a roundnose bit? I would think this would be more do-able with one rotating neck instead of 4 unless you are planning on setting up a factory..:-).

have you ever done a fretboard with a ball nose? it leave a terrible finish with lots of tearing and takes ages.

and the jig has 4 sides for different opperations, and yes, the entire point of this thing is for a small factory.

[luthier]

Well you asked for thoughts.....Yes I have used a round nose router bit for fretboards, in fact I radiused my fretboards with a straight router bit for a decade with a regular router in a jig I designed. You need to sand the final surface with the varying grits before fretting anyway so a little more with a radius block isn't that tough. It just seems that developing a machine to then go to a belt sander adds a lot more problems to the engineering of it. Good luck on your venture.

[ihavenofish]

the problem with the ball nose is it tears the wood alot on the surface and edges. sanding is better for rouging making the machine do the sanding is not hard.

ideally id be using a custom concave spiral carbide bit, but they cost $300 each, and you need one for each radius, so they dont make sense for variable production runs.

[Kevin Waldron]

Not sure what you guys are talking about on fret boards and ball nose?

We use a 3/4" ball nose at 6% step at 600 inch/per/min(machine never max's out in the short distance...... not sure the actual speed) and 20,000 rpm.........takes little or no sanding and the time is 6.5 minutes per fret board. No chipping or tear out.

Kevin

[judleroy]

I have also had good luck with cutting a compound radius fretboard with a ballnose. The tool was 1/32" dia. There was no tearing and the finish was almost as good as finish sanded. I used a .025 flat endmill to cut the inlay cutouts and fret slots. This was done on a machining center not a router at 8000 rpm. The last op was the profile with a 1/4" tool. Total machining time was maybe an hour. The sander would make things quicker so it's not a bad idea to put it under Cnc control if your not doing compound radius boards. The jig is a great idea for small production runs so good luck with it.
Judleroy

[ihavenofish]

Originally Posted by judleroy .....Total machining time was maybe an hour.

thats where the problems start. 1 hour in my shop = a $200 fretboard. doesnt make much practical sense when your trying to sell the entire guitar for $599

thats why the jig and machine is the focus here, to make things like fretboard radii fast and easy. a minute or 2 for a radiussed and slotted fretboard is an upper limit.

when youve only got a few guitars to make a week and selling them for several thousand dollars, none of this is that important.

[judleroy]

How many of these are you trying to make in a week? If it's as many as you seem to imply it's probably not even worth your time to machine them in house.(wow 200.00 dollars an hour. I wish I could get away with charging that). Stewart McDonald offers pre radiused and slotted fingerboards at pretty decent prices.
Judleroy

[ihavenofish]

Originally Posted by judleroy How many of these are you trying to make in a week? If it's as many as you seem to imply it's probably not even worth your time to machine them in house.(wow 200.00 dollars an hour. I wish I could get away with charging that). Stewart McDonald offers pre radiused and slotted fingerboards at pretty decent prices. Judleroy

i thin youve over looked the entire point of the setup. its to be able to handly variable designs efficiently in production. last i checked stew mac doesnt hand 8 string 24 fret multi scale fretboards in purpleheart...

the production rate im looking for is around 300-500 necks a month from one machine.

[judleroy]

If you get a chance I'd love to see some pictures of the models you will be offering. I have been playing for years and am always interested in seeing quality instruments.
Judleroy