Back bow

[ScottZ]

I just picked up a used 2014 MIA telecaster with a Warmoth modern construction neck, 59 Roundback, flame maple, SS frets and rw fretboard.  And with strings 9df and truss rod loos it has back bow.  Is the double expanding truss rod able to correct this if I keep turning it counter clockwise?  Sorry if this is a dumb question, I've never used this type truss rod before.

 

[Cagey]

No. Warmoth uses what they call a "double-expanding" truss rod, which implies it moves in both directions, but what it actually does is make two moves while tightening to accomplish what a single truss rod normally does. This allows for a somewhat simpler neck construction while providing for greater stability. But, unlike a "double-acting" arrangement, it won't compensate for back bow.

For what necks cost these days, back bow = death knell, but if you're determined to salvage it you can sometimes bake it out. I've done it in the past, and described the process here if you're interested. It's actually not that tough to do, doesn't take long, and costs nothing so it's worth a shot before you give the neck up to the dog for a chew toy.

 

[ScottZ]

With 11s on it, it's playable, I may just use heavier strings than I normally use and replace it sometime in the future.

 

[Unwound G]

Depending on the level of backbow which I assume is not that drastic if you are able to counter it with 11s.  One thing you can do is loosen the trussrod and apply pressure at the center over time to condition the wood and fretboard to a flatter in-situ level.  What I usually do is to form a "bridge" by resting the neck heel and headstock on some thick books.  I will add weights on the center of the fretboard and let it sit for a few days. Check the neck occasionally for any changes.  You may have to keep adding more weights if there are no changes.  You can give this a try and quite safe since your neck is a '59 Roundback.

 

[dmraco]

If 11s correct it, Cagey's method can fix it. 

If that scares you a bit, string it with something HEAVY!!!  13s or 14s!  Keep it in a proper-humid environment for some time and give the neck a change to adjust.  IT may just bring it back to shape...a bit more slowly than Cagey's method however.

 

[Cagey]

It really does require heat. Just stressing it, even excessively and for long periods, won't do it. The last time I tried the stress trick I strapped the neck into a neck jig and forced about 1/4" or better of relief into it and left it that way for weeks. Literally. When I let it up, it just sprung back to where it was.

Makes sense when you think about it. If simple stress alone would do it, all necks would just fold up not long after being strung up. String pull is in excess of 100 lbs, even with light strings. Also, truss rods wouldn't work. You can loosen a truss rod that hasn't been moved in years and the neck will relax into it's original form. If the combined stress of compression and torsional force from the truss rod won't permanently move the neck, what's a few weeks of heavy strings or any other artificial distortion gonna do?

 

[AirCap]

Cagey is correct about the heat. Prolonged heat will affect the lignin in the wood (which is not completely dry unless it has been baked or roasted), allowing the grain of the wood to deform or slip into a new position. You want it almost too hot to touch for as long as possible, then insulated once the heat source is removed. The residual heat can do its job while forcing the neck into the new position (allowing for springback). Quick removal of heat and quick cool down will result in new stresses to the wood.

Back in the 80's, I did a lot of heat pressing of necks on Les Pauls for bowing and twisting. It does work, but it's not an exact science.

 

[ScottZ]

With 11s on it, it's playable with no fret buzz, but still doesn't have much relief at all.  I may go to 12s and just live with it.

 

[Cagey]

One could argue that if it's playable with no fret buzz, then there's not a problem. It takes a very level set of frets to get away with that, which is a Good Thing. Relief is a compensatory adjustment, not a requirement. In a perfect world, you'd need no relief at all.

The problem comes when we talk about "playability", which is highly subjective. One guy's "playable" guitar is another's useless nightmare. Often, you can compensate for a less than ideal fret plane or lack of available relief by raising the bridge high enough that there's sufficient string clearance to avoid interference with string vibration. But, is it playable set up that way? Depends on the player, but most would prefer the strings fairly close the fretboard.

If the thing is playable for your comfort level using the strings necessary to get it to behave, then you don't have a problem, right?

Personally, I'd have a pretty rough time playing 11s, but that's just me. There's certainly a population of players that are comfortable with that gauge set, or there'd be no such thing.

 

[sadman]

If the frets are tall enough,is it possible to level them in a back bow position with 16" or 24" long leveler?

 

[TonyFlyingSquirrel]

I have a very light touch & pick attack when playing lead, so I rarely if ever buzz when doing so.
However, I do have a heavy picking hand when playing rhythm, and that is when buzz can introduce itself in my playing, so I have to compensate with a tad higher action that I would actually prefer.
I'm learning to hone back my rhythm picking to allow lower action, which will facilitate more relaxed playing, preserving hand/forearm health.

You'd think I'd learn how to play after 45 years of it...

 

[ScottZ]

Cagey, can you tell me what kind of shim you went with on your final attempt? Was 1 neck plate enough?

 

[Cagey]

I'm pretty sure that's what I used. Just be sure your reference (the bar you're clamping to) is perfectly straight.

Oddly enough, I'm about to try that trick again today, and that's what I'm gonna use. I've got a neck here off an old Univox from the '70s that's been a real problem child, but I'm slowly winning the battle. If I see this thread again, I'll update.

 

[ScottZ]

Thanks.  Hopefully I can tackle this soon.  I still need to figure out what to use as the reference.

 

[ScottZ]

To answer the earlier question of playability, with 11s and a high action, it rarely buzzes.  I'm not very comfortable playing this way though, I prefer 9s and a lower action. I believe the action is currently about 2.8mm, I believe that translates to 7/64".

 

[Cagey]

Well, "perfectly straight" may not be a strict requirement. But, it needs to be able to take the heat without moving, and you need to be able to measure how much you've bent the neck before you cook it. If you can satisfy those requirements, you're probably good to go. As Aircap mentioned earlier in the thread, it's not an exact science. It's kind of a "hail Mary pass", so to speak.

 

[Rick]

I tried bending without heat treating on a fender maple neck.  It worked. I don't know why, just lucky I guess.

 

[Seamas]

I have a question regarding the heat treatment.

Though is sounds like it works just fine, I was wondering if there was any benefit / detriment to having a more humid environment in the oven?
Or is that overkill?

I know when they bend wood for furniture they will basically steam it.

I also know cooks/chefs will have a tray of hot water placed on a lower rack when they need a more humid oven.

 

[Cagey]

I'm just guessing, but I'd say it wouldn't be helpful. Makers go to a great deal of time/effort to dry the wood out to about 4% or so, so adding moisture probably isn't a great idea. Also, anyone's who's left a guitar in a damp basement or otherwise humid area can usually tell you what a mistake that was.

 

[ScottZ]

Cagey, in the thread you linked you mention using a reference beam of 18", is that a typo?  The picture looks like it's shorter than that.

Thanks