Official Luthiers Forum!

I'm preparing to route the groove for the truss rod in
my current build. I have a couple of questions.

First, I'm building from the OLF SJ plans.

I've purchased a two-way "Martin style" truss
rod made by Gotoh from LMI.

http://www.lmii.com/CartTwo/thirdproducts.asp?CategoryName=T russ+Rods%2FNeck+Parts&NameProdHeader=Truss+Rod+%2D+Martin%9 9+Style+Truss+Rod

It seems that most folks here orient their truss rods
so that the adjustment end is accessed through the
soundhole. I've read comments by Cumpiano (and others)
that reversing the direction and allowing for adjustment
via the headstock introduces some weakness to the
headstock area (I'm using a scarf-joint Sapele neck, not
a laminated approach).

But I've also seen plenty of guitars made with the truss
rod adjustment in the headstock.

I'm leaning towards doing it this way also. Frankly
its because I don't see how to pre-drill the access holes
in the neck block and upper transverse brace with
sufficient accuracy. I saw one builder with on-line
construction photos who took a router to the assembled body and routed out a groove right through the top
of the assembled body (and into the neck block, brace and graft) to provide access. That looked extreme to my
inexperienced eye.

Here's my question: If I want to orient the truss rod
for headstock access, where should the other end of the
truss rod end? It looks like it will need to extend
past the 14th-fret body join line about 1/2 inch into the tenon.

Is this OK? Should I have purchased a shorter truss
rod (I already wish I purchased a *lighter* one)?

Can anyone describe how they locate the access hole
when doing it the other way around (soundhole access)?
Do you pre-drill the neck block before assembling the
body?

Thanks,

Eric

Eric-
Good points, and interesting questions. I've been building with the adjustment through the soundhole, and I certainly like the appearance of the headstock without truss rod cover and screws.
As you point out, the truss rod adjuster does complicate things in the neck block area, and if you plan to use a straight allen key for adjustment, you have to think about holes through the transverse brace, etc as well. I've been drilling the hole in the neck block after body assembly, but the rest of the access path for the key is done before the top goes on. Generally I tend to err on the 'too much clearance' end of the spectrum- I don't want things binding in there. BTW, a ball-end allen key can help if the alignment turns out to be a bit 'off'.

However, I think I'm going to switch to headstock adjustment in my next few projects. For me, it is easier to adjust the rod from the headstock end (especially with strings on the guitar), and I'd like to have a bit more freedom to plan the bracing without thinking about how to get the allen key in there.

It's a decision between esthetics and practicality for me. There are some alternatives to traditional trussrod covers which help with the 'ugly' factor on the headstock. There was a good article by R.M. Mottola in American Lutherie #86 (GAL magazine) about headstocks and trussrods-worth a look.

I wouldn't be too concerned with having the truss rod ending in the tenon. The important thing is to think out the cross-section at the headstock end. I've only used a Gotoh rod once, and I 'ended' the routed slot with just enough clearance space to get an allen key in (you can chop off part of the short arm of the 'L'). It's not necessary to 'run the slot through' the headstock, which you see sometimes. A volute can help to beef up the neck a bit in that area as well.

Cheers
John