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I have a relatively simple fixture I use to hold a neck blank face down to shape the back of the shaft between the heel and the headstock. Just a board,really, with a strip to fit into the truss rod slot, holes for pins to register the jig to the table, and a block to register the heel.

What my fevered brain has been trying to work out is some jig to hold the neck blank's headstock parallel to the table face up so I can profile it and drill tuner holes. It has to register from the center of the neck blank, be able to register to the table, and hold the neck blank securely and aligned properly.

Every solution I come up with feels too elaborate or requires too much preping of the blank. For example, my blanks are not always the same exact width. Sometimes I do a stacked heel and scarf joint, sometimes I laminate three pieces that were profiled on the machine, sometimes I accent with veneer, etc. I am not sure how to hold the blank in the jig without drilling holes for pins from the bottom where they can't be covered up by a fingerboard. In any case...

I'm curious to hear what other people are doing, if your willing to share.

Has anyone come up with a jig that will let a 3axis machine do the back and headstock of a neck?

Thanks.


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Machine the tuner holes from the back in the first process, then you'll have holes to use for indexing and bolting if you're not going to use vacuum.

I've thought of coming in from the back for the whole profiling and hole pocketing. Front or back, I'd still have to find a way to hold the headstock parallel to the table, wouldn't I? With only 3 axis machine, if I machine the tuner holes while the fretboard face is flat on the table the holes would be at a 15deg angle. I keep thinking of some kind of pivoting mechanism, but can't seem to come up with something reliable and accurate that will still hold the neck in place.

This got me thinking, and this is what I came up with. I've never tried it, but it looks logical.

First, make some hold-downs screwed to the scratch board, and drill the center tuner holes:


Then make a riser block, allow the neck shaft to hang over the edge of the table, and mill the rest from the front:

The only problem I see with the first jig is that you would need those first two tuner holes to be placed very precisely relative to the blank's centerline and relative to the ultimate nut location. At the very least the jig that holds the blank for machining the shaft needs to easily align or register to the jig that holds the headstock for drilling the first two holes.

I'm not sure how to do that quickly and repeatably.


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Profile the headstock to a known shape to provide reference edges so that it will fit into a mold fixture when doing the shaft-up ops. IE an oversized square paddle, or really anything. Make a "mold" fixture out of some scrap 8/4 mahog with a pocket that shape. Then it fits into the mold in exactly the right position and can be brought down to your profile. Hold with vacuum or good DST. You may be able to cut the profile of your headstock in the shaft-up setup using z-waterline operations for the features that can't just be profiled. Still use the mold fixture with the shaft hanging off the table to drill your tuner holes and pocket for inlay.

This how I do that.

Let me know if this isn't self explanatory and I'll fill in the blanks.

One thing....the divots are not exactly 1/2 rounds....more like 1/3 rounds...so that they can be milled at an angle and not elongate the circle when the mill approaches the headstock surface at its angle.

This works very well. I cut the divots on the operation that cuts the neck shape, ,tongue mortise, volute area, headstock back, and the rough headstock shape (I leave .1" around the profile). Flipping it over I then cut the fretboard gluing surface, the truss rod groove, and the headstock gluing surface (I use a facing). The headstock gluing surface is cut with a surfacing operation...at an angle.

I use a tool LIKE the one pictured. This conveys the idea though. This allows the final surface of the headstock to be faced, the tuner holes to be MOSTLY milled (a quick hit with a reamer finishes them), and the headstock profile to be cleaned up....all while maintaining the cad model integrity.

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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 like it. The divots and nubs would have to be a really good fit.

Igot some ideas from Randk and others.
This will give an idea of the side profile










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Ken

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Ken

You can see the angled headstock has a section to hold it down to the spoilboard with a bolt.

Truss slot





I then use a sander to face it smooth.

Thanks to Dan the CAD guru for the programs.



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Ken

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Ken

Then i gluu on the face veneer with hile placement for the drillpress.


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Ken

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Ken

Thanks to all. I'm working on a solution similar to Stewarts, and will post pictures after a successful test.

Ken, yours is the most interesting! I had to look at the pictures several times to understand what was going on. I'm still not sure how you present a horizontal headstock for profiling, inlay, and tuner hole drilling. Still yours wins for the most "CNC" way of doing things. It looks like you are using the machine to cut your blank and "jig" all in one piece. So inventive! Perfect registration with the neck face up and face down with no jig involved. Love it!


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Ok, reading the last sentence in Kens post I think he is profiling the headstock at an angle and cutting the headstock veneer separately. The tuner holes and inlay is done on the face plate and then glued to the headstock. That only leaves drilling tuner holes manually using the veneer face plate as a guide. Is that right?


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Yes that's right.
My requirement to Dan The cad guru was to toolpath from a blank that would yield to necks which measures 3 x 4 x 30. The standard neck blank. The profile operation leaves a skin so that The profile cut outs don't become loose. I finish that off at the bandsaw. Then I cut them to a width of 2.5 inches. Drill holes in the waste to bolt down to my table. And I can route the truss rod slot from the top zeroing on the centerline and at the top. then when that operation is finished flip it over and route the back profile including the tannin to exact thickness the headstock profile and the shaft with transitions.
Remove that and I'm ready to glue on the face veneer which has previously been nc ed. This leaves a little handwork to trim them together flush them together I mean. Then on the drillpress I drill using the hole placement. I have a step spotfacer to widen the quarter-inch hole to fit my bushing.


Edit. After the machining process I cut off the extra at the end where the tab was and I sand the face plate surface and fingerboard service hundred percent flat and true. It doesn't take much just a few minutes flat sanding surface. The back of the headstock also gets a few swipes I actually use a drum sander to taper the headstock



I press in my logo and shield when the glue is wet after it has been clamped an hour I remove the clamp call and press in my logo and shield. Then I reclamp.




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Ken

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Ken

It seems to work for me.


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Ken

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Ken

Ok, I finally got around to using the setup I described earlier. Here's how it went.

I use a riser block, trued with the CNC, and mount the neck with two screws through the headstock area. The CNC program is keyed off the break point of the headstock.

Once the tuner holes are drilled, I screwed it down through them and removed the other two screws.

Then I turned it around and screwed it down through the heel area to cut the truss-rod channel and neck outline. I used a wedge to support the neck and make sure the Z axis was aligned front to back.

I mace an MDF fretboard, just to show how it all looks together.

Here's a link to our neck build. (We are in the process of changing it to be a bit more efficient.)
We built multiple fixtures on the table, but you should be able to get some ideas from this.

https://www.youtube.com/watch?v=xXkXsypBuAA

Pete that gives me some good ideas for when my cnc comes in (3 weeks) I sold my first cnc and I'm ready for the new one to come in

I think Stuart's method is the best one, but I've done production necks doing what Rand said: I mill the headstocks square on three sides when they're face down and then use those to index in my face-up fixture.

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Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services

I like this. I currently don't need to register the head plate so accurately so I'm making mine such that the top surface is replaceable for when I do need to register it accurately.

thanks!

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