Official Luthiers Forum!

Hello, my name is Josh Garrett and I program and operate the CNC machine at Galloup Guitars in Big Rapids, MI. I'm going to use this thread as a view into how we integrate the CNC machine into the projects we do here at Galloup. I would love to hear how others do similar jobs as well.

Today I am working on some electric guitar bodies a few of our current and former students ordered recently.


This is a double cutaway, carve top, bolt on neck, electric guitar body the student wanted. It has a flame maple cap and a 3-piece alder back.

_________________
Josh Garrett
Galloup Guitars CNC

Great looking carve - did you digitize off of a carved part and run code from that or did you design it in CAD and then run code?

Either way, looks like a good result!

Trev

_________________
http://www.PeakeGuitars.com

Thanks, we took some measurements from a few guitars with a height gage and calipers, then designed in CAD. We don't have a probe yet but I'm looking into getting one.

_________________
Josh Garrett
Galloup Guitars CNC

That Guitar looks really good!

What software are you using to design your models, and what CAM package are you using?

_________________
-CyborgCNC
http://www.cncguitar.com
https://www.facebook.com/CncGuitar

Thanks, I use Rhinoceros and RhinoCAM for all the CAD/CAM design work we do here.

Today's update, I started out cutting a rosette for one of the Galloup guitars. I didn't take any pictures of it while it was cutting but here it is after it was cut and some of the inlay pieces were put in.

I will finish cutting it tomorrow, after the glue dries.

The rest of the day was filled with design work for one of our clients. I was finishing up the drawings and toolpaths for his flat-top electric guitar body. No pictures yet but I am cutting it tomorrow so hopefully I can post some images then.

_________________
Josh Garrett
Galloup Guitars CNC

Nice work...great minds think alike I guess...!

_________________
http://www.PeakeGuitars.com

That looks good Trevor.

Here is the rosette cleaned up and with flag installed.


Today I'll be cutting the last MDF guitar body prototype, then finishing the neck for it and cutting that.

_________________
Josh Garrett
Galloup Guitars CNC

"The Borealis" Eh?

Cool.

_________________
John Mayes
http://www.mayesluthier.com

Very nice....that finsihed up rosette

I noticed the lack of continuous keylines around the inside decorative section and that the outside ring was laid in as a continuous piece...since the fretboard can cover the gap. I expect making the fit precise is impossible without sectioning off these inside pieces. I'm very impressed with this design considering this limitation....real nice.

Have you ever tried simulating a continuous line though? I'm imagining a way to join the edges of the inlays such that they can all be glued up together but still be in sections.....and butt up to their mates. You just have to make a jig that allows you to machine the ends all the way down through the base stock....and take about .002" off the ends of each section.

I guess that will only make sense if you're doing your inlays the way I think you are.....male pre-assembly, female, glue, face off?

What diameter, rpm and feedrate are you using to make those corner cuts?

_________________
I read Emerson on the can. A foolish consistency is the hobgoblin of little minds...true...but a consistent reading of Emerson has its uses nevertheless.

StuMusic

Yes, the guitar is called The Borealis.

We cut and assemble our rosettes in several steps
1: Cut the inlay pieces 0.010" smaller than the pocket they will drop in, in this case 8 spalted maple pieces and one flame maple piece for the flag, all 0.005" oversized in thickness.
2: CNC cut the pockets for the spalted pieces in the top.
3: While the top is still vacuumed to the CNC, glue in the spalted pieces.
4: Now cut the 0.023" slot around the spalted pieces as well as the slot for the black zig-zag pieces around the rosette.
5: Remove the top and inlay 0.020" black in the slots that were just cut. Dry overnight.
6: Place the top back on the CNC and cut the pocket for the flag.
7: While the top is still vacuumed to the CNC, glue in the flag.
8: Cut the 0.023" slot around the flag as well as all the small slots in the flag and the 1/16" holes for the Morse Code.
9: Off the CNC to inlay the flag border and flag details.
10: Thickness sand to flat.

It's a lengthy process but we get great results.

As far as the corners, I use a 0.023" cutter at 18000 RPM (our max rpm) with a feed rate of 20 IPM

_________________
Josh Garrett
Galloup Guitars CNC

Interesting. Thank you very much for the details.

Seems the only way to improve that would be to take the top off the machine and be able to accurately re-register the top back on the tool....so you could glue off-line while another one is cutting....if that's even an issue.

I'll describe the process I use in case it adds an idea. I first cut a flat surface and a male relief boss on the backside of a raw piece of wood. This boss fits into a female groove on a metal vacuum fixture with a nice slip fit. Doing this allows me to find the origin on the corner of a metal tool and take the part on and off the tool any number of times. This allows for an infinite number of very fine wooden, metal, or plastic keylines to be built all prior to gluing it into a top or fretboard....or whatever.

At any rate......no one can argue with what you're getting.....what a fine looking result!

_________________
I read Emerson on the can. A foolish consistency is the hobgoblin of little minds...true...but a consistent reading of Emerson has its uses nevertheless.

StuMusic

Thanks, glue time isn't really a big deal, we're using CA to glue in the large pieces so after a matter of minutes I can cut the borders for the inlays.

Yesterday was the first time cutting the carve-top, set-neck version of the Nukleus. I have been working on this for Omar of 3rd World Guitars. I cut the final MDF prototype of the flat-top, bolt-on neck Friday.

I cut the jig to cut the back later that day. I'll be cutting the back later today.

_________________
Josh Garrett
Galloup Guitars CNC

Is that a particle board vacuum jig, or are you guys using double stick tape for prototype stuff (looks like there are some phenolic vacuum jigs in the back?)

Nice stuff!

_________________
http://www.PeakeGuitars.com

For prototypes I just use double stick tape on particle board. For production parts I am using phenolic vacuum jigs.

_________________
Josh Garrett
Galloup Guitars CNC

Cool thread. I focus on electric guitars and have a 3925. Just wondering how you guys are approaching the angled headstock/tuning machine holes on necks. I have made a wedge base with indexing holes, but would like to see others ideas and fixtures.
Are most using HSS or is there a benefit to any of the other materials for your main profile and shaping cutters?
Thanks,
Mike

I machine my tuner holes & headstock from 4/4 mahogany, then scarf joint it to the neck shank. I have alignment features on the headstock and the shank that keep them aligned. This way, I can make everything from 4/4 lumber and I don't have to worry about angled jigs, etc..

Trev

_________________
http://www.PeakeGuitars.com

The only HSS in my shop is in drills. The price difference is so small now in smaller-sized cutters (<3/4") that there's no real reason to use HSS unless toughness is required (like in drills).

_________________
Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services

I calculated how high the headstock face would be off the cnc table if it were 0-180 degrees. It turned out that it was about an inch higher than the vice so I made a tooling plate that is held by the vice.

The headstock is held in place by the tooling plate and the heel of the neck rests on the table.

It sounds hokey but it works well...I'll get pictures of this when I get out in the shop tomorrow.

_________________
I read Emerson on the can. A foolish consistency is the hobgoblin of little minds...true...but a consistent reading of Emerson has its uses nevertheless.

StuMusic

As of now we do most of the peghead work by hand. I cut the overlay out on the cnc but the rest is done by hand. I'm slowly working on a jig to hold the face of the peghead while I cut the back as well as a method to quickly and accurately bring in the angle by hand. As far as tooling goes I almost exclusively use solid carbide tooling. Most of which is meant for metal. I get amazing tool life and they cut well.

Yesterday I cut the top of the neck for our clients guitar. I'll be cutting the back in a few minutes. Then cutting and arch-top set.

_________________
Josh Garrett
Galloup Guitars CNC

I've done that on customer necks, depending on what had to be done to the headstock. Slotted heads with relief need to be machined face up, for example. If you inlay the headstock after the plate is on then same deal; that's what Taylor does.

_________________
Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services

The idea is that my tuner post holes need to be concentric to the inlays on the headstock facing.

The divots are milled into the back of the headstock during the operation that creates the whole neck. You can mill these divots into a 15 degree surface and they will still be placed properly within that plane...so that's pretty handy.

The tooling plate is pretty simple. Part of my thinking on this was to try a "soft" holding fixture. It's based on locating those divots in the headstock to the bumps on the tooling plate. Now the neck is registered to a known origin and any operation can be done to the headstock or the headstock facing after it is glued.

Yes...that's surgical tubing that holds the neck to the plate during machining ops....works great. On the table I clamp a block on each side of the neck heel to keep it from wiggling back and forth during machining. Once that is stable the whole thing is STABLE on the tooling plate.....though you might not think it to look at it.

_________________
I read Emerson on the can. A foolish consistency is the hobgoblin of little minds...true...but a consistent reading of Emerson has its uses nevertheless.

StuMusic

Two questions come to mind.

1. why do you use slots to index instead of pins - either separate pins or male pins routed into the wood?

2. What's the purpose of the long bolts and surgical tubing on the end of the headstock profile fixture?

No particular reason. Since I have to mill the backside flat anyway it's only a small matter to incorporate some kind of registration geometry. The shape isn't important as long as it functions.



The surgical tubing wrapped around the neck and these bolts is what clamps the neck to the tooling plate during machining ops.

_________________
I read Emerson on the can. A foolish consistency is the hobgoblin of little minds...true...but a consistent reading of Emerson has its uses nevertheless.

StuMusic

I've been doing a few projects for the last couple weeks. First off I cut the second prototype neck for our client Omar along with 2 fret boards. All out of MDF.

This is the updated heal shape. I also updated the reenforcement rod pockets to the new size and shape.

Later in the week I cut a few fret boards for our Great Lake Guitars line.

Here the machine is cutting the perfling slot in the side of the board to give it a bound look.

Earlier today I test cut and then actually cut a back stripe for a Galloup Borealis guitar.

_________________
Josh Garrett
Galloup Guitars CNC

Are you putting a thin line of purfling around the outside edge of that fingerboard or are you just making a binding channel? If so...I've never seen anyone cut a binding channel like that....are you having chipout or fixturing problems? Just wondering why you're using the slotting saw..?

Inquiringly,
Trev

_________________
http://www.PeakeGuitars.com