Neck Bolt Alignment Techniques

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Alexander Higgins
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Neck Bolt Alignment Techniques

Post by Alexander Higgins »

This question is particular to a Steinberger bolt-on neck, but I suppose could apply any time you are making a new guitar body for an existing neck that doesn't have standard fender bolt patterns:
Image

What's the best method for transferring an existing bolt pattern from the neck to the neck pocket? I have not had great luck with transfer by measurement and layout. I thought I could use something like dowel centers, but they wouldn't fit the bolt holes. The neck heel holes have brass metric-thread inserts for machine hex-head bolts. I thought I could try putting some cut-off bolts on an angled support and grinding the heads to points, screwing them almost flush into the holes. and then tapping the neck into the pocket to create drill guide indents. Is there a better way?

Dave Stewart
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Re: Neck Bolt Alignment Techniques

Post by Dave Stewart »

You probably could use dowel centers, either the smallest mortise ones(3/16) in the holes or larger tenon ones over stub screws threaded into the inserts.
http://www.leevalley.com/en/Wood/page.a ... 42288&ap=1
Alternately, you could put in the screws, "chaulk' the heads & tap into pocket to mark locations.
Dave
Milton, ON

John Sonksen
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Re: Neck Bolt Alignment Techniques

Post by John Sonksen »

You could also do a rubbing with a crayon onto a piece of paper, find the centers and use that to make a template. I was actually looking at your other thread a couple minutes ago and thinking about how you were going to do this.

Alexander Higgins
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Re: Neck Bolt Alignment Techniques

Post by Alexander Higgins »

I actually took micrometer level measurements when I drew up the original CAD drawing, but based on my experience effing up the neck pocket, I don't trust my measuring techniques, too many opportunities to screw it up. I think I actually have some 3/8" dowel centers kicking around, if they fit on the bolt ends, I'll try that, if not I'll go the chalk or carbon paper route. The dowel center or pointed bolt idea has the advantage of creating a centerpoint dent for the drill, rather than trying to eyeball the center of a chalk mark. Another thing I didn't think through carefully in my enthusiasm to cut out the body. Another question: how much slack should there be between the neck bolts and the holes through the body? None, 1/64"?

Dave Stewart
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Re: Neck Bolt Alignment Techniques

Post by Dave Stewart »

I meant to say, I'd avoid the hand ground points... I doubt they'd be accurately centered unless you did it on a lathe
Dave
Milton, ON

Jeff Highland
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Re: Neck Bolt Alignment Techniques

Post by Jeff Highland »

Alexander Higgins wrote:I thought I could try putting some cut-off bolts on an angled support and grinding the heads to points, screwing them almost flush into the holes. and then tapping the neck into the pocket to create drill guide indents. Is there a better way?
Whatever you do, don't screw in pointed cut-off bolts till they are nearly flush. you will have no way of getting them out!
I have done this with pointed bolts but only screw them in to where there is still enough parallel section to grip

John Sonksen
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Re: Neck Bolt Alignment Techniques

Post by John Sonksen »

All this stuff about using centers to give locations for drilling sounds like a lot more work than necessary, and might screw things up anyways. I thought the neck needs to go in at an odd angle with respect to parallelism between the face of the body and fretboard? If that's the case you're going to be scratching those points all along the bottom of the neck pocket as you go and not have a good center point anyways. I'd say, take the measurements carefully, reference them from the obtuse edge of the heel, draw them out on the back of the guitar, and drill them out slightly oversized. You don't need to have threads for the screws to engage both the neck and the body, in fact it could hinder the joint getting tight if both WERE threaded.

I wouldn't spend that much time on this. Mark it out check it ten times if you want, put a backer block in the pocket so it doesn't blow out and go for it.

John Sonksen
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Re: Neck Bolt Alignment Techniques

Post by John Sonksen »

Or you can also cut a blank of wood the width of the heel, hold I parallel to the heel and mark out the center of the holes directly from the neck. Drill them on that piece and try attaching it to the heel first. If it works, you can use that for a template or even a drill guide

Alexander Higgins
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Re: Neck Bolt Alignment Techniques

Post by Alexander Higgins »

I had already pictured myself screwing the pointed bolts just... a .. little.. too far in... Doh! The next image is of me trying to hacksaw slots into the ends of hardened steel bolts for a slotted screwdriver. The Horror.That would be painful indeed.

The heel tapers in two directions, end of neck tapering toward nut and top of fingerboard tapering down to neck pocket, but it will drop straight in from above, in fact that's the only way it WILL drop in because of the compound wedge shape of the pocket, so any center pins I can jigger up can only drop straight down into the pocket. The top and bottom edges of the neck have about 1/8" radius on all edges, so it's really hard to reference a measurement against anything, since there are no sharp angles, hence my reluctance to rely on direct measurements. I actually have a lucite template of the bolt holes that I used to register a couple of the bolt inserts in the bottom of the neck that had failed and had to be epoxied in, but it's not sized to the neck pocket. I suppose I could use that template to make another one to fit the neck pocket. I'm liking the idea of a template if I can't see a way to use dowel centers.

Thanks All

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Peter Wilcox
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Re: Neck Bolt Alignment Techniques

Post by Peter Wilcox »

How about short (shorter than the hole depth) round or oval head Phillips machine screws, screwed all the way in. Then insert the neck in the pocket and whap it down a few times. That might leave cross marks on the pocket where you can drill the holes. If they don't show up adequately on the wood, you could put some tape down first, or put some type of pigment in the Phillips grooves.
Maybe I can't fix it, but I can fix it so no one can fix it

John Sonksen
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Re: Neck Bolt Alignment Techniques

Post by John Sonksen »

My concern with trying to use points is you are going to be elevated off of the face of the neck pocket by at least the height of the points right? And so the holes will not be in their final locations unless you actually fit the neck right down against the pocket. This will be the same with panhead screws or even set screws (headless with allen key drive facing out, though you could probably get closest with those). Unless you can press those dowel centers all the way in until the neck is flush against the floor of your neck pocket, (which you can't because every set of dowel centers I've seen have a flange that goes around them to keep them from being pushed into the part you're using to index the holes from), you'll give yourself a false reading. If you used some kind of dye or paint on the end of screws, same thing it'll be messy and leave a lot of room for error. What if you took some cardstock, like a 3 X 5 card, held it against the base of your neck and carefully pressed in the areas where the holes are? Use something with a rounded plastic head that's larger diameter than the hole to just create a dimple, and not punch all the way through. You could easily do this and draw an outline of the heel onto the card as well so you can then cut it to fit into the neck pocket. If you want you can either find your centers on the dimples that will be produced and drill them out or even use a hole punch, voila instant template that you can verify inside your pocket because it's thin enough not to get kicked sideways by your wonky neck pocket and it's crooked walls.

Warren May
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Re: Neck Bolt Alignment Techniques

Post by Warren May »

I think John's idea of using a thin template with centerpunch at the hole locations is the most appropriate for this application so that you make sure the neck end and sides are in the correct orientation to the pocket. A thin piece of wood would also work by "inking" the neck with something that will transfer the outlines.

Alexander Higgins
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Re: Neck Bolt Alignment Techniques

Post by Alexander Higgins »

First of all, I must lodge a protest at the terms "wonky" and "crooked" in relation to my neck pocket! "Compound Bevel" sounds much more impressive (ok, it started out wonky, but has improved recently to "good enough for government work"). Whilst clamping the body to my workbench, I managed to create a perfect indented impression of one of the drywall screws holding the masonite top in place into my mahogany body, so I know that would work in the pocket (plus now I have experience steaming out dents) but the cardstock template idea is good too, love this forum!

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