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Post by blademaster2 on Nov 19, 2015 14:09:54 GMT -5
Hello,
I have a 1967 Teisco MJ-2L that is in nice condition and sounds unique but with only one problem - a neck back-bow. It is very slight but bothersome. This guitar is fun, sounds quite good and has a great whammy bar design. I would enjoy it a lot more if I made it play well.
I have already tried to bring it forward by trying the following home-made neck press attempt: clamping it into a forward bow using nylon bands (with an already-loosened truss rod, of course) and running a hot but dry iron on a dry towel placed over the fretboard. This warmed up the fingerboard a little and was done in hopes of creating the necessary forward bow permanently. It possibly made some slight improvement but not enough.
So now I am considering taking the following more drastic steps, in order of preference/invasiveness:
1) Do the same with the hot iron but use a moistened towel so that steam is injected into the fingerboard, then quickly clamp the neck into a slight forward bow and wait until everything settles and cools. I am hoping this would reverse the bow and then could be fine-adjusted using the truss rod.
2) Perform a full fret job on it, correcting the slight back-bow by a combination of slightly reshaping the fingerboard and dressing the new, higher frets to further compensate. [This can only be done for very slight change over what is there and it may be insufficient.]
3) Remove the fingerboard (and probably the frets), re-glue it back onto the neck but clamp it using a wooden form to give it the slight forward-bow that I want (I have the same form with which I used this technique on my homemade guitars and it has worked, giving two-way adjustment). Then, of course, install and dress new frets.
Is there any advice out there from some experts?
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Post by cynical1 on Nov 20, 2015 23:49:14 GMT -5
Well, you were on the right track for part of that. Before I offer what to do, let me give you something not to do. When putting the neck under pressure you may not want to wrap the neck in hot wet towels. Sure, it might help bow the neck...but it just as easily might twist\warp the neck. This is a stable piece of 50 year old wood. More than likely stable, but why chance it. It's only going to happily go so far anyway.
So, if it was me, I'd get a sanding block or three, a strong piece of square tubing, or channel stock and a clamp.
Next, I'd take out the truss rod nut. Clean it up and as much of the thread as you can see on the rod. Put one sanding block in the middle of the neck on the fretboard with the fretboard facing down, take the two other sanding blocks and put them on the back as close to the heel and headstock as they'll go. Take your sturdy piece of whatever you have and lay it on top of the two sanding blocks on the back of the neck. Now take your clamp, put one jaw on the sanding block on the fingerboard and the other jaw on your sturdy piece of whatever. Then gently apply pressure until the neck reaches your desired spec. Go slow and listen for the wood talking back to you. It does whisper before it cracks...
Once you're there you can take that nice clean lubed nut and screw it onto the cleaned threads on the truss rod. Tighten it to where it feels snug but not forced. Remove the clamp and put the neck down for 3-5 days. If it looks good after that, you're done. If not, rinse, lather, repeat...
CAVEAT: This is a 50 year old piece of wood. Stable and hard. Being patient will likely reward you with a neck that'll probably never move again. Act in haste...well, you get it.
Make Sense?
HTC1
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Post by Deleted on Nov 21, 2015 3:32:04 GMT -5
repent in leisure! BTW, Cyn1, BladeMaster how about just putting a (much) heavier strings gauge (possibly with the truss rod completely loosened or even removed) for a while? As a first step before the more drastic courses of action. Heavy gauge and perfect straight neck and low action is the shredder's dream! And could serve as the No1 practice guitar. + Heavier gauge strings sound better, sustain better.
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Post by b4nj0 on Nov 21, 2015 4:35:06 GMT -5
Following on from GD's suggestion; how about a refret with smaller tang frets? May sound drastic, but offered in the interests of exploring every avenue.
e&oe...
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Post by cynical1 on Nov 21, 2015 4:43:19 GMT -5
Here's the thing. That truss rod at 3/16" or 1/4" (4mm-6mm) diameter just isn't going to move that big piece of maple or mahogany. Over time, the strings might, but the rod is really only there to hold the shape, not bend the neck by itself. This is why they strip out or break loose. You really need to push the bend and lock it with the truss rod once the bow\backbow becomes severe.
With heavy strings, while they do have a fuller tone, you actually need to raise the action. They move a lot more as they vibrate and will buzz out on you if you try for the same action you have with .07s.
In Blademaster's case, that neck took 50 years to walk out that far. You need to apply easy mechanical force and then lock it with the truss rod to make it playable again for another 50 years.
HTC1
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Post by Deleted on Nov 21, 2015 13:34:37 GMT -5
But with the heavier strings the ellipse is of lower magnitude because of higher tension. Wouldn't this compensate for the larger string diameter?
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Post by cynical1 on Nov 21, 2015 14:53:48 GMT -5
Try this experiment. Put a set of .13s on your shredder setup guitar. Don't worry about the nut or the saddles, the strings won't be on there that long... Because it'll buzz like Hell...provided you even get a note out of it. By the time you've got the buzz out you've moved well past shredder territory. You will normally need a truss rod adjustment relatively soon after going to that gauge on a good neck. Not having seen the guitar in question, I can't say just heavier strings would do much more than make the instrument unplayable. HTC1
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Post by Deleted on Nov 21, 2015 16:03:51 GMT -5
Why don't you try this experiment Cyn1 : on a balanced set (each string has exactly the same tension), try to setup the action height exactly the same for every string. Does the A buzz worse than than D? (I wouldn't think so.). How does the buzz on A and low E are compared? Now lower the action even lower to the point all strings start to buzz. Now tune the low E as A. Compare again the buzz. The thicker ex-E now-A should buzz noticeably less than original A. So we have two strings that sound the same, and the heavier gauge buzz less. That's why ppl with lower tunings use heavier gauge strings. To retain all setup (truss rod, neck relief, overall tension, string height) the same, except for the tone. A floppy string will create larger ellipse and buzz more on the center. Cyn1, with all respect, I have done all sorts of the above tests.
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Post by blademaster2 on Nov 23, 2015 13:56:41 GMT -5
Wow, thank you all for your time on this and your valuable opinions.
I agree with Cyn1 - and I would never wrap the neck with moist towels anyway but I was considering what the added steam might do, but only on the fingerboard - but I will take another route. Also, the back-bow is fairly small - around 1mm across the length of the fingerboard.
I think that first I will try the added force suggested by the heavier strings (possibly I could clamp it in my neck form and achieve a similar result, faster). If that does not help then I would turn to a re-shaping and re-fret. The existing, original frets are old and fairly worn so it probably will benefit from this regardless of the back-bow. That will, of course, require a new nut ....
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Post by cynical1 on Dec 4, 2015 11:35:42 GMT -5
Just one last note on all of this. Maybe I said this before, but I'm too lazy to go back and look...HOWEVER...the truss rod is there to HOLD the position of the neck relief. It's there to support an already strong piece of wood. It's not perfect, but the purpose it serves it serves pretty well.
My only concern with slacking the truss rod completely and letting the strings pull it over time is the possibility of a twist or warp developing. Your neck is 50+ years old. It probably isn't going anywhere. However, someone with a new guitar, where many manufacturers only kiln the wood versus aging it, trying that with young wood will see markedly different results. I'd hate to leave this without at least dropping this caveat in place.
As far as the balanced string sets...I've never played with them. Greek, your results with them peaked my curiosity. What's your recommendation on a set of .013s? Can you get them in flatwounds? (It's a bass player turned guitar molester thing...)
Happy Trails -
Cynical One
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Post by Deleted on Dec 5, 2015 5:22:55 GMT -5
Cyn, I've never gone beyond 12's on electrics, and this was for drop tune purposes. I am afraid if you want to go flat wound, you might collect each one individually based on e.g. daddario tension charts. From what I searched there is no balanced set for flat wounds.
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Post by cynical1 on Dec 5, 2015 14:09:13 GMT -5
The .013s were just part of the experiment on Project #2 (aka Blue Murder) to create the fullest, darkest tone I could. Normally I use .010s or .011s on the guitars. I like the .013s because of the wound G string, but after a couple of hours they can get tiresome.
The flatwound thing is a carryover from the bass. They're easier on the fingers, have a certain warmth to them, which I would define more as "tone rolled off" versus dull...and you never hear a finger squeak on the tape later... Only the wife's guitar has roundwounds and that's gonna change if she ever wears them out. On an acoustic is makes for some interesting tones.
I'll take a look at the D'Addario site. Again, now you've got me curious...
Happy Trails
Cynical One
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Post by blademaster2 on Dec 8, 2015 10:03:12 GMT -5
Thanks again to all.
Update: I currently have the neck clamped into a forward bow in a form that I made years ago for guitar construction. That keeps it straight and with an even, untwisted contour. I will leave it like that for several weeks more to see if the wood can undergo plastic deformation and then have a look when it comes out. *Hopefully* it will need a slight truss adjustment at that time to straighten out the residual bow to the desired contour and it will be good to go. Then I might decide to do (or not do) a re-fret and give it a new nut so I can enjoy even more the unique tones of this little instrument. Comparing it to a Les Paul, Stratocaster, ES-335, or my home made guitars I still get a unique, warm, chime-like tone from it and I enjoy using it in the odd recording.
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Post by cynical1 on Dec 8, 2015 11:00:26 GMT -5
So, with the neck in the fixture, clamped to the desired relief, where is the truss rod nut? By that, I mean is it still backed all the way off, or is it snugged up?
HTC1
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Post by blademaster2 on Dec 8, 2015 11:01:10 GMT -5
The truss nut is loosened completely (I am glad I did not forget to do that).
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Post by cynical1 on Dec 8, 2015 17:41:01 GMT -5
OK, good. Now, while it's in the fixture and clamped to your desired relief, can you tighten the nut on the truss without bottoming it out on the threads? Without forcing it, of course...
Might be a good time to take the nut off, clean it out, put some grease on it and then see if it holds before you run out of thread.
If it does hold, you may very well be able to take the neck out of the fixture and be ready to go with it.
Happy Trails
Cynical One
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Post by Deleted on Dec 9, 2015 4:24:18 GMT -5
OK, good. Now, while it's in the fixture and clamped to your desired relief, can you tighten the nut on the truss without bottoming it out on the threads? Without forcing it, of course... Might be a good time to take the nut off, clean it out, put some grease on it and then see if it holds before you run out of thread. If it does hold, you may very well be able to take the neck out of the fixture and be ready to go with it. Happy Trails Cynical One Assuming that the fixture's tension is equal to the tension of the strings right? Also how about putting some washers after the nut in case it doesn't hold? (Or did I screw up with my understanding)
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Post by blademaster2 on Dec 9, 2015 9:50:22 GMT -5
Roger on the lubrication of the nut (I might try dry lubricant, like graphite).
The form is holding the neck with slightly more forward bow than I want in the end, in the hope that the residual plastic deformation will still require a slight truss adjustment (giving two-way adjustment, ideally).
I will post an update, probably in the New Year, when this next step is finished.
@greekdude, there is lots of thread left on the rod that is visible, so I think it will be good (if it runs out on the inside then I will add washers as needed)
Thanks to all for the valuable advice on this.
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Post by blademaster2 on Jan 4, 2016 13:31:26 GMT -5
Well, here is an update on my Teisco MJ-2L neck:
I held the neck clamped in a gentle forward-bow for about three weeks, then took it out and observed that it immediately returned to the slight back-bow that I saw on it before. I have now tried forcing it into a slightly more pronounced forward-bow in the clamping form and will see what it does, but I am losing hope.
The next step might well be to re-fret the neck and give the fingerboard a re-shaping in the process. I have avoided this up to now, but beyond that I can only see more drastic measures (as already mentioned in earlier posts).
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Post by cynical1 on Jan 4, 2016 14:19:19 GMT -5
Was the nut snug on the truss rod when you loosened the clamps?
HTC1
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Post by blademaster2 on Jan 5, 2016 15:37:29 GMT -5
Hi Cyn1,
No, I have not done anything with the truss rod nut - it remains loose. As a one-way adjustment rod, I am expecting to want it to remain loose until I have the neck (hopefully) with a slightly exaggerated forward bow that I can then adjust back to the desired relief using the truss adjustment nut.
Are you thinking differently?
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Post by cynical1 on Jan 6, 2016 0:19:24 GMT -5
Are you thinking differently? From my experience, I know it to be different. Let me try to be brief... When a big solid piece of maple or mahogany decides after a decade or three that it wants to move, do you really expect a 3/8" or 10mm piece of steel to move it back on it's own? Of course not is the correct answer here... The clamps you used to move the neck into its desired relief were a good start. But to expect what took 50 years to transpire was going to be straightened by a few weeks clamped up was asking a lot more than you were about to receive. While the truss rod is truly not strong enough to modify the relief of a neck that much, they are completely capable of holding the relief you've set with your clamps, or at worse, a sizable portion of it. Your bend is not what you normally see. Most cases you use this method to put in some backbow. Either way, the process is the same. The only problem you might have is enough thread on the rod...it sucks when you wind up with not quite enough of them. But we can cross that bridge if we come to it. So, if it were me, I'd set the neck relief in your clamps again, then check to see if you can snug the nut on the road while the neck is clamped. Leave it for a coupe of days and check the neck again. You don't want to over tighten the rod, but you'd like it snug. After that, pull the neck from the clamps and measure the relief. Within reason, you can get away with doing this a couple of times if you're cautious. It's best to let the neck sit for a few days, then remeasure first. Once it all looks good, put it back together and string it up. Happy Trails Cynical One
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Post by Deleted on Jan 6, 2016 5:58:31 GMT -5
I think I understand Cyn's spirit. I think the idea is to "train" the truss rod to follow the up bow while still having some purchase on the threads. Then you will have both the desired relief + a working truss rod.
As an alternative idea, I'd like to ask, is this truss rod removable? If yes, why not install a double action (two-way) truss rod?
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Post by blademaster2 on Jan 6, 2016 9:27:42 GMT -5
Many thanks once again,
@cyn1, I am still confused, but possibly because I am only familiar with the one-way truss design that I was taught by my luthier mentor many years ago. In my own home-built guitars, the truss rod is installed into a channel with a glued-in insert on top of it that is shaped so the rod will pull back on the neck when it is tightened, creating less relief (or a back-bow). As such it operates only under its tension, and its own stiffness to bending is negligible. Loosened all the way, as it has been for this clamping exercise, it can only alter the neck profile if tightened and then again only to pull back for less relief. I have expected that my Teisco neck operates the same way.
Nonetheless I have given the rod's nut some mild snugness now, as you have suggested, while the neck remains in the clamps with a pronounced forward-bow. My expectation (acknowledging that it differs from yours) is that when it comes out of the clamps the truss nut will again be loose due to the relaxation of the neck back from the clamped forward-bow profile. I will let you know what happens when I do this.
@greek, no, unfortunately the rod is not removable (unless I remove the fretboard and dig it out).
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Post by Deleted on Jan 6, 2016 10:19:50 GMT -5
Nonetheless I have given the rod's nut some mild snugness now, as you have suggested, while the neck remains in the clamps with a pronounced forward-bow. My expectation (acknowledging that it differs from yours) is that when it comes out of the clamps the truss nut will again be loose due to the relaxation of the neck back from the clamped forward-bow profile. I will let you know what happens when I do this. Cyn's concern is not to potentially loose purchase on the threads, that is why he suggested fastening the truss rod enough to have some hold on it. Also (If I understand Cyn very well) if the neck behaves well enough as far as up the bow or straightness are concerned, while the truss rod is lets say half-way tightened, then you will have some chance getting a little bit more up bow, by loosening it a bit.
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Post by cynical1 on Jan 6, 2016 10:40:42 GMT -5
The truss rod works best as a stabilizing device. Depending on how it's installed it can compensate the relief of a neck due to seasonal changes, or string gauge changes. It is not designed to "move" the neck. Tightening or loosening the nut on the rod will only effect the neck to a small degree. Major changes, if the wood can take it, really require the nut to be loosened, clamp the neck to your desired relief and tighten the nut on the rod.
The concern about the thread applies to a backbow repair in that it won't be long enough. Your concern is the opposite in the there may not be enough thread cut into the rod to allow you to tighten it enough to hold your clamped relief.
Keep in mind, if the neck develops any twisting the only fix is to pull the fretboard and replane the neck. No fun.
I hope this works for you.
HTC1
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Post by blademaster2 on Jan 7, 2016 22:56:14 GMT -5
Hello again,
Well, I took the neck out of the clamping form just now and it returned *immediately* to pretty much the same back-bow as before - and the truss rod nut loosened itself from the mild "snugness" as this happened (it then accepted another 1/3 turn to get it back to the same 'snugness' that it had before I took it out of the clamp).
Not good, but certainly no harm done and I am back where I started.
The best repair might be to remove the fretboard and replane the neck, then reglue it back on (or glue a subtle forward bow into it rather than replaning anything). However I do not think this is really worth it for a Teisco and for such a minor amount of backbow (I could even simply replace the string nut with a higher one, and live with the higher action).
Given that the frets are skinny and low - not to my preference - and that the backbow is reasonably minor, it might still be worth my effort to refret the neck and gently reshape the profile into a slight relief before installing the new frets. A new, higher string nut would be needed also, of course, to accommodate the higher frets.
Thanks again for all of the advice!
Any additional thoughts or comments will be appreciated.
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Post by Deleted on Jan 8, 2016 9:08:51 GMT -5
How about the heavier strings? Did you put them on?
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Post by blademaster2 on Jan 8, 2016 11:40:38 GMT -5
No, I have not yet tried that. Thanks for reminding me, as I might do that next time I am near a music store and can pick up a set with 'suspension bridge cable' gauge.
The amount of clamping force I applied in the form was, in my estimation, much more than the strings would impart so it will surprise me if I could actually pull it into the desired relief that way. This old neck is a fairly hefty, three-piece construction using mahogany. It really seems to want to stay the way it is.
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Post by Deleted on Jan 9, 2016 1:13:18 GMT -5
Don't know. With all my axes except an old Aria strat (i.e. Carvin DC135, Kramer 210, Ibanez ARZ800, Ibanez UV70p) a slight gauge/weather change have quite an impact on relief, but a light truss rod adjustment is all that is needed to bring it back to "nominal" values. Who knows, maybe they don't make'em like they used to. Maybe older guitars are more immune to tension applied.
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