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About 6 mos. back I decided to whittle down the neck on my 3rd build , a couple of guys said it felt too "meaty", I took it out today and I'm pretty sure that the truss rod is blowing out. I've never had this happen before on any "store bought" or otherwise. I put a mic on it and it is at 0.82" just below the first fret. I mic the Gallagher G-70 that I use for a model and it is at 0.90" at the same place. Guess I get to build another neck. I'm gonna leave tthe next one "meaty". So do any of you go below 0.900"?

That's scary because I just finished one with a really thin neck. It is for my young son. I profiled the neck between the size of a Martin 000 and his Yamaha JR guitar. I better go measure the neck.


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What kind of truss rod is in it?

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Steve Smith
"Music is what feelings sound like"

It's a Stew Mac hotrod dual action. It probably would not happen even with a thinner neck using a single action with the nut at the peghead. The wood is Solomon Island rosewood, laminated with the grain standing perpendicular to the fretboard.

Sorry that happened. When people have called my necks meaty it was never the thickness, rather that I left the neck too squared off more a blocky D shape than a C shape. I fixed it by better rounding the neck.

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That explains it. The hotrod needs a very deep slot. The kind using a metal strip instead of a second round rod will let you do slim necks like this. http://www.stewmac.com/Materials_and_Supplies/Truss_Rods/Low-profile_2-way_Truss_Rod.html

Or as you say, a single compression rod works too. Those go close to the back of the neck, but their pressure is exerted in-line with the grain, rather than toward the back of the neck like a dual action rod.

The hot rod requires a .4375" deep slot. Assuming your fingerboard is 1/4" tall, then a neck that is only .82" thick has only .11" of meat beneath the truss rod. That's less than 1/8". Recipe for failure!

well I get 0.133 but your right , I should have done the arithmetic before whittlin on the thing. Oh well as the true French say "vire et appendre" (live and learn) I don't know what those folks across the Sabine from me say

All of my necks (mahogany) so far have been right around 0.80" thick at the first fret. The thinnest was 0.79". I've been using the LMI double action truss rod that's 3/8" thick which leaves about 0.175" of meat. No problems to report. Was the truss rod cranked pretty tight?

I agree with John's comment. If a neck feels too meaty, the first thing to look at is if the shoulders of the neck profile are too thick. Reducing the shoulders can go a long way to making a neck feel less of a hand full.

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That is why I prefer the LMI rods. The Hotrods require too much depth.

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The ole SM Hot Rod ruining your whole day thing again....

We've been to this movie before ourselves setting up a very high end Les Paul that a small builder crafted. One initial turn of the SM rod and it split the neck.... Not a good day....

We've also read around 1/2 a dozen accounts of this happening over the years and if you noticed SM now caries a low profile rod.... likely because of the issues associated with the added depth needed for the regular hot rod.

Allied, Blanchard rod fan here - always check the welded nut first though.

Use the Martin style U channel rod that you epoxy into place and you will never have to deal with this type problem.
Tom

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Yep, it's the Hot Rod. I've only had one one blow out and it was a Hot Rod too. Looked about identical to yours which is why I asked. I fixed mine by removing the fret board and truss Rod. I repaired the blow out, put a wood strip in the channel and installed a shallower rod that also extended a bit farther towards the headstock. I also put on a new fret board but only because I messed up the old one removing it. I used a Rod from Allied for the repair but now would use a Martin dual-action as they are a bit slimmer. A pain in the butt repair but that neck has been played daily for 4 or 5 years so I know the fix is good.

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Steve Smith
"Music is what feelings sound like"

I was on a thin neck kick with my own guitars (after owning a Gibson Johnny Smith with a factory custom order thin neck). With traditional single truss rods I've had no problems going absurdly thin. So thin that on two of my favorites I'm probably going to add some more wood to the back, they just don't feel right to me anymore. But after many years they are still great stable necks. I suspect the tone will be better with more neck wood.

Since this build I've gone to making my own single action rods and installing them with building an upbow into the neck as I saw done on a Dan Earlewine tip

So, this is the brass block pushing through the back of the neck? I'm assuming that the adjustment is on the body end.

Aside from the additional 1/16" or so of depth over the Allied style rod, is there an inherent problem with the design of the Hot Rod? When it comes to counteracting string pull, any double-action rod is going to put the most pressure at its ends pushing on the floor of the channel, and somewhere along its middle pushing on the underside of the fretboard. Is it the squareness of the brass end blocks in the flat-bottomed channel at that thin area of the neck that creates an unusually high stress point? All things being equal - 1/4" fretboard, 1/8"-5/32" behind the end of the rod - is the Hot Rod really that much more prone to blowout than the Allied style rod? Or is it just the user's error, underestimating the safe thickness of the neck at that nut-1st fret area?

Yup, good rod, shame about the depth.
Only use them now if set in hard neck laminations (eg maple or sapele) an someone wants a reasonably deep neck.

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The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

I use Martin Rods and specs --- Two-way minimum .20" backing Single action minimum .24"

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Ken Cierp

http://www.kennethmichaelguitars.com/

So I guess this thread should go into "removing a fretboard with..." Anyway, that's where I'm headed.

It's a pain but you'll be glad when it's done.

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Steve Smith
"Music is what feelings sound like"