Official Luthiers Forum!

I've been using M&T bolt-ons for my last two guitars, and I'm having a bit of a challenge in getting the bolts perfectly aligned with the fastening nuts embedded in the neck. I'm following the process outlined in William Cumpiano's website. http://www.cumpiano.com/Home/Articles/S ... block.html

It's working, but I'd like to improve the alignment of the holes - for the barrel and the bolt. Currently the method I use is to measure and mark with a pencil, then carefully drill with a hand drill. No major problems yet, but it has required some widening of the holes to align the bolts and barrels to support a tight fit.

Do I just need more practice, or is there a technique that I'm missing? Thanks.

A block of wood with a centerline that registers off the top surfaces with the bolt hole location drilled through. 1/4 holes for the body and tenon face, then drill neck blank side enough to mark centers and then through with your 3/8 brad. I usually widen the tenon face holes by 1/32. As all holes are located with the same jig everything lines up. I'm sure I learned that from someone here.

I've used marking points like these in furniture projects.

http://www.leevalley.com/us/wood/page.a ... 42288&ap=1

I'm working to close the box on my first git...so I haven't had a chance to apply it to the M/T neck connection. Sure, a jig would be more precise and repeatable, but I think these would improve over the measure and mark method.

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rono

1. Take some bolts that fit in your neck hardware. Cut the heads off with a hack saw or dremel. Cut them so they are about 1/4" ish long sticking out of the neck.

2. Chuck them up in a hand drill.

3. Sand points on them by running your drill and using a stationary sander.

4. Put them in your neck.

5. Press firmly against your neck block

6. Mark the spots

7. Drill and countersink for bolt heads.

Presto... perfect alignment.

One piece of advice. Make sure the neck is pretty close to being set correctly (without the fingerboard installed) before you do this. The closer it is to final fitting the more accurate the holes will be.

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Brock Poling
Columbus, Ohio
http://www.polingguitars.com

You can just use a set screw. put it in the insert sticking out about .125, press the neck in place. It leaves a mark and then drill.

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John Mayes
http://www.mayesluthier.com

Alternatively, you may be interested in a tutorial I did
viewtopic.php?f=10117&t=16049
for bolt-on archtop neck.....drilled through endpin hole to provide matched alignment.

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Dave
Milton, ON

This is pretty easy - With the body complete, drill the holes in the neck block, hold the nearly completed neck in place and mark with a pencil through the holes in the neck block.

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"An adventure is only an inconvenience rightly considered. An inconvenience is an adventure wrongly considered." G. K. Chesterton.

Check- out LMII's neck joint video using KD fasteners same as Cumpiano.
O'Brien transfers the hole locations from the tenon onto the mortice using a machinist scale.

http://www.lmii.com/CartTwo/Video.asp

Brock's method is what I use for all kinds of things; it's creating a custom transfer punch. Lee Valley sells sets of them cheap; I got a set from somewhere else a long time ago and ended up using them far far more than I ever suspected I would. They make all kinds of problems go away

http://www.leevalley.com/US/wood/page.aspx?p=54892&cat=1,43456
http://en.wikipedia.org/wiki/Punch_(tool)#Transfer

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Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services

I tend to do this a little different so pass it a long also.
I make my heel block complete with the mortise for the neck tennon cut and the holes/counterbores for the neck bolts drilled before glueing it in. I'm not so sure this is smart, as it presents a few assembly challenges, but it's what I do.

So, when I'm drilling my mounting holes I take a piece of scrap that fits my tennon snugly and slide it in to the bottom of my heel block. When I drill my bolt holes I drill through this "stick" also at the same time, giving me an exact copy of the location of the bolt holes.

Then when I'm ready to transfer the holes to the tennon, I place the stick into the guitar body and mark the hieght where the neck tennon will meet the top and I glue a little stop there. Then I glue a scrap to the side of the stick to provide side to side alignment. I'm now precisely registered agaist 3 sides of the tennon and can accurately drill my holes.

I've never had and alignment problem with my system and is really not much extra work.
Here a photo of a stick.

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Jim Watts
http://jameswattsguitars.com

[quote="Jim Watts"]I
So, when I'm drilling my mounting holes I take a piece of scrap that fits my tennon snugly and...

Should read "mortise snugly"

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Jim Watts
http://jameswattsguitars.com

They call them dowel center transfer plugs at amazon. I have heard them called any number of things. They are a main stay of finish woodworkers. I seem to need them when building stairwells and custom hand rail. They work great for your purpose. Just drill the holes in the neck tenon, put centers into those holes and stick the neck where it wants to go. Pull it out and you will have marks where to drill.


General Tools 888 1/4-Inch to 1/2-Inch Dowel Center Transfer Plugs

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http://goatrockukulele.com

I've been making my headblocks with the mortise and bolt holes already fashioned for standard models. Alignment really has not been a problem for non-cutaways. (For cutaways with a flush heel I cut the mortise after the box is closed and drill the holes with a drill guide that fits in the mortise.) After the tenon is cut I position the neck, mark the location of the holes with a transfer punch through the headblock holes and use the jig below to drill the holes. (Copied from a Mark Swanson post on the MIMFF 6 or 7 yearsago.) I use another transfer punch to align the jig with the marks. Although I have not seen a failure to date I now reinforce the tenon with maple strips and flood the wood with CA. Hole sizes are 3/8" headblock and 5/16" tenon. 3/8' for the barrel nuts widened to 10mm with a reamer.





If you drill after the box is closed a reverse spotfacer is a nice way to countersink the hole from the other side.
The "Yard Store" in Witchita KS has them

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It's not what you don't know that hurts you, it's what you do know that's wrong.

What a great combination of recommendations! Clearly there are a lot of effective ways to skin this cat. Thanks - I'll experiment with the recommendations.