Well, I'm working on an old Epiphone arch top circa 1949/50 that has a loose fretboard that clamping pressure won't close. It has that antiquated compression truss rod and the neck is bowed right where the shaft of the neck transitions to the heel.  This is also where the thread anchor/nut thing is "inlayed" that the rod goes through.  

The fretboard is probably loose because of the combination of string tension bowing the neck and the compression rod pushing up on the fretboard.  The existing truss rod can't be inlaid deeper into the neck without contacting the top of the guitar or inlaid deeper into the fretboard without making the FB too thin.

So to solve the problem I either need to:

1) add material to the neck to raise the floor of the bowed area

2) replace the truss rod with a conventional Fender style rod that has a U-shape bend to it.  

Anyone out there accomplished this repair?  What was your approach?  Are there other options I'm over looking?

FWIW, I'm also doing a neck reset and refret.  I pulled the fretboard today, here are some pics from my phone:

Tags: Epiphone, Rod, Truss, Vintage

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Looks like the truss rod is mounted too high for a compression rod, and the end near the body is too far out towards the middle of the neck, causing the bend right there. Had a similar situation, and replaced it with a two way rod, and it worked perfectly. That looks like a very big diameter rod, so if you go that route, you may need to glue in a piece of wood, then route the proper size channel for the rod.

That's a great view of the infamous Epiphone "Thrust Rod."

 They rarely work well because they sit right under the fretboard and try to stretch the neck from there, rather than sitting low in the neck, compressing the back of the neck the way Gibson rods do.  Clearly, it was an attempt to have an adjustable rod without infringing on Gibsons early patent.

You should definitely abandon that system in favor of just about anything else - heavy carbon fiber reinforcement, or whatever adjustable rod you can get in there.

Thanks for the advice guys.  I'll talk to the customer.  I like the carbon fiber idea; it's not a very valuable guitar and installing an adjustable truss rod would be very time consuming in this case because it would have to be crescent shaped in order for the nut to clear the top of the box.

I own a 1940 Epi Zenith, a great guitar, but with the same ineffectual rod. If this guitar( being discussed) is not very valuable, and were mine, I would install a truss rod with the access at the headstock. Epiphone began installing the rods in this manner right about the early 1950's.

I've had a couple of inquiries from forum members about my progress so here's an update.  I started working on this project again today.  I've settled on a 70's Martin style square tube non-adjustable truss rod which will require a little router-work to widen the existing channel.  My old truss rod channel routing jig works but is less than ideal.  Consequently, I've made a new one dedicated to ⅜" square tube rod installations that works with a down-cut bit guided by bearings.  I'll attach a photo from my phone of the new one below.

Okay, it's been a while since I sought the community's advice on this one.  Regardless, I thought you all might be interested to see how I went about the repair and how it came out:

Yep, very interested!  Thanks for the followup... great information and wonderful work! 

Thanks Mike.

Ditto to what Mike wrote... with a couple ++'s added.

It's really great to see this.  More often than not, we get & answer questions and give advice, yet rarely have the opportunity to see the 'fruits' of the forum's efforts, especially when performed by such a highly skilled craftsman.

Thanks again, Nathan & kudos :)

That's way beyond my pay grade! Thanks for the update.


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