[thumber]

Hi,
Perhaps someone can lead me to a source, or can draw/explain the Burns truss rod, installed on my 1976 7660 Gretsch. I'd like to know how they mechanically work and appear in the neck. The reason I ask this is because, my Nashville model has one of these truss rods and I can't seem to get it to change the relief in the neck. The guitar, by the way, is all original and has had very little use—a real find!

However, perhaps I am not checking the relief correctly. I have been capoing the 1st fret and holding down the low E string at the highest fret—then checking clearance around the 7th fret. I'm lucky if I get .003" clearance. I can't say the guitar frets out in the middle of the neck, but there is some slight buzzing around the first and second fret, which probably could be eliminated by raising the bridge. I would like to set the neck correctly, regardless.

My concern is that I have turned the truss rod key many, many turns CCW with no change. It seems the number of turns is limitless. I can't believe the truss rod is dislodged, because this guitar is in near-new condition and I'm sure I'm the first one to ever remove the adjustment plate on the back of the guitar (I happened to get the guitar with all the original tags, truss key still sealed in the factory envelope, etc.). There is even, moderate drag when I turn the adjustment key, so nothing seems "broken" about it.

So, by seeing the actual mechanism, I might be able to determine if the truss rod is actually damaged/dislodged, or perhaps the key post is disengaged. My other thought is, perhaps this truss rod works on an eccentric mechanism (cam-like), so all adjustments can be done in 360° of key rotation. Maybe my constant turning of the key is simply going through the tightening/loosening cycle each revolution.

I have light strings on it (.010-.046) and intend to put .011-.052s on it today, thinking that the increased tension might increase the relief.

I have searched all over the internet for some answers, but don't seem to find anything of use. A photo, drawing or a detailed explanation would be greatly appreciated.

[Synchro]

I'm no expert on the Burns gearbox except to say that it has a reputation for not being reliable. It was an idea that was somewhat forced upon the Gretsch company in the Baldwin era and like most things Baldwin did it turned out to be bad for the brand. I'll scout around and see what I can come up with.

[thumber]

Thanks Synchro for anything you can find.

[Jukebox]

I was taught to cappo the first fret and go to where the body and neck joins,and press on the strings to see where the relief at.

[thumber]

I just received a response from Burns of London concerning the Burns gearbox adjustment. Their response was:

"The Burns Truss needs many turns to get small adjustments, it has a 16 / 1 ratio gearbox."

So, at this point, I'll keep gingerly turning that adjustment key and see what happens.

Thanks again to all that have responded!

[Synchro]

Originally Posted by thumber

I just received a response from Burns of London concerning the Burns gearbox adjustment. Their response was:

"The Burns Truss needs many turns to get small adjustments, it has a 16 / 1 ratio gearbox."

So, at this point, I'll keep gingerly turning that adjustment key and see what happens.

Thanks again to all that have responded!

Get an air ratchet.

[tartanphantom]

that ratio is approximately the same as many tuning machines. so if you can visualize how many key turns it takes for one complete revolution of the stringpost on a tuning machine, then you can get a pretty good idea of how many turns it takes for the gearbox to make one complete rev on the truss rod. Excellent for micro adjustments, but a major pain if you have to adjust the neck more than a few mm.

And yes, the gearboxes have been known to strip out.

[kalimantan]

Hi, Thumber did you manage to adjust the truss-rod? If so, what/how did you do exactly? I'm having similar problems.

[charlie chitlins]

Originally Posted by Jukebox

I was taught to cappo the first fret and go to where the body and neck joins,and press on the strings to see where the relief at.

Yup. Going to the last fret is for bolt-on necks.
For set necks, go where the neck joins the body.
And... .003" would be OK in the middle if you're not terribly heavy handed.
Any relief at all is usually enough.
With all the things that folks obsess about on guitars, neck relief doesn't seem to be one of them.
A little daylight between the string and the fret that's in the middle is fine.
If you're getting buzzing after proper trussrod adjustment, look at the bridge and saddles, and see if there's a "hump" in the fretboard around where the neck joins the body. This is pretty common for hollow guitars as the neck joint shifts.

[charlie chitlins]

And..........geared truss rod adjustment?
Yikes.
I love it when somebody comes up with a complicated solution for a problem that doesn't exist.
Not.

[coolbus18]

Originally Posted by charlie chitlins

And..........geared truss rod adjustment?
Yikes.
I love it when somebody comes up with a complicated solution for a problem that doesn't exist.
Not.

It reminds me of when I owned British cars.

[thumber]

Sorry for not seeing your posting. Yes, the truss did manage to come around. the 11-52s pulled the neck into some relief and I was able to fine tune it. Now that the humidity has changed, I recently turned the truss rod key 4 full turns to reduce relief and am still working with it. So, the thing about Burns truss rod adjusters is that they require several turns to make a definite adjustment, then you turn back the other way to fine tune it to your liking. Just don't force anything and work slowly.

[hartwell]

Thanks for posting this thumber - I have a 77 7660 and it's useful to have this info in case I run into a similar issue later. I've heard some horror stories about this system - glad to hear it worked for you.