Neck Adjustment Without An Adjutable Truss Rod?

[Johnny GUitar]

Hello,

I'm new here though I've been to the Project Guitar pages a few times and have been very intimadated by the quality of work I've seen. So this is a reapir question and not a building question (I hope that's OK here -- I couldn't find a guitar repair forum like this). I did try the search function here and didn't find anything involving my question (but I did find a few rather humorous exchanges involving truss rods ).

I have recently acquired an old Silvertone Kay. I believe it's a Value Leader model guitar from the late 50s or early 60s. I intend to use it for slide so I'll probably use medium to heavy gauge strings and I'll be changing the tuning a lot.

I immediately noticed a fairly bad bow in the neck such that it frets out above the 12th fret entirely. There is no truss rod adjustment (is it possible that there is no truss rod?).

I have done a procedure where the neck is heated and clamped to remove a bow to an old P-bass neck (I did this twenty years ago, this procedure was rather easy and worked perfectly and still holds up today). Unfortunately, I can't remember the specifics of how its done and since there is no truss rod adjustment, I want to get it right the first time.

Here's what I would do (as close as I can remember) if no one can help me:

1) remove the neck from the body and place in an oven heated to about 150 degrees F for about 20 minutes (this heats up the glue between the fingerboard and neck and gets it soft).

2) Immediately remove it from the oven and put it into a clamping mechansim (two small wood blocks, one at the nut and one at the highest frets against a piece of angle iron parallel to the fingerboard, with a "C" clamp at the apex of the bow on the back side of the neck clamping to the angle iron -- all protected with pieces of carpet as to not mar the wood).

3) After snugging up the clamp (so the neck has not moved) tighten up the clamp until the neck is first straight, and then a bit (?) more (introducing a slight front bow) in order to counter act the string tension and over come the initial bow. (Since my neck under string tension appears to have a bow of about 3/32" I was thinking of going to at least 1/32" of front bow)

4) Leave in the clamping mechanism for several days.

Then reattach the neck and restring the guitar.

My main questions are about the oven time and temperature and how far to reverse bow the neck in the clamps. If anyone can give me any advice I'd really appreciate it.

I will say that this procedure is not that rare (the one I did on my P-bass was under the guidance of a freind who was studying lutherie and he seemed pretty matter of fact about it). It is mentioned briefly in Dan Erlewine's Guitar Player Repair Guide. I would recommend people might want to learn this procedure as it can cure an otherwise seemingly unplayable instrument.

Thanks,

John B.

[westhemann]

the truss rod adjustment is probably on the heel where you will have to remove the neck to adjust it

[Hoser Rob]

First off, there may very well not be a nut at the neck heel ... you can't assume an old guitar will have an adjustable rod.

Putting the whole neck in the oven may soften the glue joint between the fretboard and neck, but it'll also soften any other lamination that may be there and ruin the finish too. I think you're supposed to apply heat just to the fretboard itself and then clamp it. I've known of people using steam from a kettle, and it works, but this'll cloud the finish too.

However, I don't think the problem is just a simple bow, though I'm not suggesting there's not too much relief. How would too much relief make it fret out above the 12th fret? It sounds to me like there's a hump or dip in the surface of the fingerboard near where the neck joins the body. That'd have to be fixed by fret or fingerboard levelling. Have you really looked at it with a straightedge?

There's a good article on evaluating necks at www.coloradoluthiers.org with a good graphic illustrating the sorts of problems you can have.

Also see www.frets.com ... it's the best web source there is for this sort of stuff, but I'm not sure your particular problem is there though.

[rhoads56]

Sounds like a pretty good way of damaging the finish to me. Id take it to a pro, those Kay's are starting to become valuable.

[westhemann]

First off, there may very well not be a nut at the neck heel ... you can't assume an old guitar will have an adjustable rod.

so why bother taking a look,right?all that pesky looking just wastes time anyway

might be a good idea to look before assuming there is not one.but i would definately not do what you are thinking of doing.

[Southpa]

No, do not bake your guitar, that is for cakes, pizzas, Sunday roast beast etc. not guitar bodies and necks. Kays are notorious for having badly set necks and truss rod problems. I found some info that might give you an idea on how to approach the problem HERE.

[Johnny GUitar]

Thanks guys.

First, there really is no truss rod adjustment. That was the first thing I was going to try when I saw the problem. I took the neck off....no adjustment (maybe no truss rod).

Hoser Rob is right, there is some sort of hump above the 12th fret (IIRC) but by putting straight edges against the frets I could see that the bow became more pronounced as it neared the upper frets (9th and 10th IIRC) and straightend out very quickly above that area. (I believe the neck straightens out there because two things happen: 1) The neck gets very thick, massive and squared off, because. 2) The neck bolts to the guitar at this point.)

So it acts like a hump but it's not in the fingerboard it's the way the neck bows and straightens out.

I know there are specialized tools for heating and clmaping necks to do this procedure, but, since I've done it in an oven before, I know it can be done without hurting the finish. (I willl note that I did actually pay more for my Silvertone Kay than I paid for my 68 Precision Bass, but I bet the P-bass is more valuable than the Kay and I intend to do all the work on this guitar myself).

I do have a concern about the oven temperature since it has to be hot enough to soften the glue sufficently, but not so hot as to damge the finish as you guys have suggested. I have to imagine 120 degrees would not be hot enough since there are deserts which have that as a day time temperature. I would think that 180 would be too hot and might damage the finish.

Just a note regarding the steam suggestion. I did a procedure like this years ago (without know what I was doing) on an old junker guitar. I used a kettle. The neck moved WAY more than I expected under clamping. I just want to add that steam has much more heat energy than water of the same temperature (physics: it takes a lot of energy to change water of 210 degrees F to a steam -- a gas -- of 210 degress) so it doesn't surprise me that using steam to do this would result in damage to the finish.

I will defintely look at the pages that Hoser Rob mentioned.

Still hoping that someone will have have experience with this procedure.

John

[Jera Woden]

im not a pro but i did something with my bass that worked but took about 3 weeks. my way might damage your guitar but it works if your not too concered about value.

i took three blocks of wood 2x4s, a long 2x4, and a huge c-clamp (10 inch i think). i put the neck in the blocks and centered it around where the most extream part of the bend was. every day i sprayed the fingerboard down heavily (dripping) with warm water in a spray bottle. the id give it about an hour and tighen up the c clamp no more than a quarter turn a day until i had a small forward bend. then i let it sit for 2 days with no water and no tightening before i removed the clamps.

this makes the wood in the fingerboard swell and ass you tighten up it helps things go back right. after your done get some lemon oil or mineral oil (what ever you want to use) and clean ith up and make sure the neck gets all it can take (it will be very dry after all that water).

i could be wrong and it hasnt been that long so i dont know if the bow will come back and i dont know if this is even anygood for a guitar opr bass but it worked for me.

[SwedishLuthier]

When you have a hump in a section of the neck like that, you will not fix it by bending the neck. The correct way would be to put the guitar in a neck jig (I know a saw a tutorioal about building one recently), pull the frets, level the fretboard, install new frets, dress the frets, and your problems are gone.

Peter

[Hoser Rob]

That's exactly what I was trying to suggest ...there's a dip or hump in there somewhere. Hopefully fret levelling will work ... levelling fingerboards on a neck with a non-adjustable rod is not for the faint hearted.

However, I still think you'd have to be able to get the neck a bit straighter than it probably is. Usually the best idea is to use heating irons, though one big enough to cover the whole fretboard ain't going to be cheap. LMI's is over $250US. That's why people use kettles, though I realize it's not good for the finish. I've seen it.

Fortunately, for slide the playability requirements aren't the same. Something like that I'd be tempted to leave well enough alone and play lap slide with an extension nut.

[Johnny GUitar]

Well, the more I look at it the more I agree that even when the neck is "straightened" out (which I still contend is an absolute necessity), it's very unlikely to cure all of the neck's ills. It is unlikely that the "hump" in the last five frets of the fingerboard (the only straight part of the neck) will remain straight, and the rest of the neck will magically unbend to it's original straight shape. (By projecting out with a long straightedge from the "hump" area to see how the neck has warped over the years, I believe it has moved about 1/4" upward; and this bowing appears to be a bit greater right before the 12th fret.)

Once the neck is straightend, I might be able to get away with a radical fret dressing above the 12th fret to make it somewhat playable, but either way I address this I will immediately run into a bridge problem (the wooden floating flat top type bridge is all the way down and the tumbscrews are gone, so if I have to raise it, I will have to do some minor surgery to the bridge).

So if I were to only look at this as a "hump" problem, I would need to remove I guess about 3/16" of material from the fingerboard in those last five frets (which seems like a lot) and refret and then do a lot of work on the bridge (probably make another one).

If I tend to go with the "bake and shake" straightening method, I might be able to get some milage out ot it by shimming the neck away from the body. When I got the guitar and first took the neck off I found a small shim close to the body which probably made the action better in the lower registers but clearly exacerbated the problem above the 12th fret. But as I said above, I agree that it is unlikely that the resulting straightness of the neck would line up with the straightness above the 12th fret.

Anyway, I need to continue reading the articles people have made reference to.

Keep the ideas coming, and if anyone can tell me what the basic temperature is on those electric neck straightening clamps that would give me a start to my original question.

Thanks,

John

[Johnny GUitar]

error

Double post deleted

Edited August 14, 2005 by Johnny GUitar

[Myka Guitars]

JohnnyGuitar, these guys are right, keep the neck out of the oven. Even if you managed to heat just the glue how would you keep the fingerboard and the neck from just sliding apart and setting up crooked? Or anything else that is glued on. This is a sure recipe for disaster as far as I can see. Don't take shortcuts unless you don't care how it will turn out.

If you have some cash you might want to take a look at one of these: neck heater. These put the heat very precisely where you want it (not all over the neck like an oven). If you do not want to do that then try one of these: repair blankets. They have one sized for a fingerboard. You can clamp this above the frets with a wood backer and prop the neck the way you want it to set. Then with the timer thye supply heat it for 5 minutes at medium heat. Let it cool thoroughly, check it, then heat again if necessary. Remeber to let it cool or it may slip out of control adn set up crooked on you. Once you heat the neck this way do not be surprised to hear some nasty sounding cracks and pops once you string it up again.

If you don't have any cash try fret leveling but if you try the oven you might not have a guitar either.

Also you may want to try the MIMF forum, they have a repair section and some good advice as well. If you do go there please tell them of your idea with the oven. They'll like that.

Just my $0.03.

~David

[Johnny GUitar]

If the idea of heating the neck is so bad and will damage the finish on the neck, why didn't it do that on my P-bass neck? Why did it fix my P-bass neck that otherwise needed replacement and now plays so well twenty years after the fact?

[jmrentis]

I do have a concern about the oven temperature since it has to be hot enough to soften the glue sufficently, but not so hot as to damge the finish as you guys have suggested. I have to imagine 120 degrees would not be hot enough since there are deserts which have that as a day time temperature. I would think that 180 would be too hot and might damage the finish.

Can I get extra cheese and pepperoni, on a thick mahogany crust, with a large maple neck to go please. Also could you put some parmesan cheese and warped neck peppers in the box.

[erikbojerik]

A lot of early Fender necks were 1-piece necks with no glue to speak of (i.e. frets installed right into the neck blank, no separate fretboard). If that's true of your P-bass neck, then the oven treatment may have only tweeked the wood for you, rather than do any glue-softening work.

[westhemann]

I do have a concern about the oven temperature since it has to be hot enough to soften the glue sufficently, but not so hot as to damge the finish as you guys have suggested. I have to imagine 120 degrees would not be hot enough since there are deserts which have that as a day time temperature. I would think that 180 would be too hot and might damage the finish.

Can I get extra cheese and pepperoni, on a thick mahogany crust, with a large maple neck to go please. Also could you put some parmesan cheese and warped neck peppers in the box.

←

this post really is useless.maybe it is just me,but it doesn't seem funny either.

as we don't want this forum to turn into a bunch of childish teasing,please refrain from this sort of thing.

[Myka Guitars]

If the idea of heating the neck is so bad and will damage the finish on the neck, why didn't it do that on my P-bass neck? Why did it fix my P-bass neck that otherwise needed replacement and now plays so well twenty years after the fact?

←

If you are set on cooking the neck then by all means don't let us stop you. Please take precautions to prevent the fingerboard from slipping incorrectly so that you have a better chance of having playable neck afterwards. As far as the finish goes, who knows. I never cooked a neck to remedy an unruly bow I just heated the fingerboard like all the repair guys do.

As before just my $0.03.

[jmrentis]

this post really is useless.maybe it is just me,but it doesn't seem funny either.

as we don't want this forum to turn into a bunch of childish teasing,please refrain from this sort of thing.

Sorry I guess we don't share a similar sense of humor.

as we don't want this forum to turn into a bunch of childish teasing,please refrain from this sort of thing.

Also there was no teasing involved. And no insult was directed, this was merely what came to mind when he posted he would be baking a guitar, just as someone else mentioned a cake, pizza, and roast beef. Thats what usually goes in an oven, so that what came to mind, I was not teasing him, as he said it has worked for him before so who am I to judge that. This place just seems a little too tense at times and a joke here and there seems in order.

Edited August 15, 2005 by jmrentis

[Johnny GUitar]

I never cooked a neck to remedy an unruly bow I just heated the fingerboard like all the repair guys do.

As before just my $0.03.

←

A HA!

Finally! Someone with experince other than me!

Do you know what the temperature of the heating mechaism is to straighten a neck? Can you tell me how far back you reverse the bow in order to make it straight under string tension? And please tell me what the "face" of the heating clamp is like (I assume it is a nicely machined flat piece of metal. Does it have indentations where the frets are? Do you need to use different "face" plates for basses and guitars or instruments of differing scale length?). I'm starting to think it might not be that difficult to make one of these kinds of heating jigs.

Now, the important stuff!

PIZZA!

Unfortunately, while I have successfuly straightened a 1968 Fender precision Bass neck (at a low temp of around 140 degrees or so), I have it on very good authority that a standard kitchen gas fired oven IS COMPLETELY INAPPROPRIATE for COOKING PIZZA!

I am not kidding!

As I understand it, you need a coal or wood fired oven which can reach teperatures of about 1000 degrees F (a gas stove won't go much above 550). That is the temperature which the real piazzarias use!

So tonight for dinner... I'm going to throw a frozen Trader joes pizza in a 475 oven and hope for the best!

BTW, there must have been a method for straightening necks before these neck heating jigs became somewhat common (I bet they were hard to come by before the 60s/70s), I wonder what they did in those days, eh?

John

[jmrentis]

So tonight for dinner... I'm going to throw a frozen Trader joes pizza in a 475 oven and hope for the best! tongue.gif

I think you'll be alright, I used to work at a Round Table Pizza, and the oven we used was at 550 to maybe 650 degrees I think, don't hold me to that but for some reason thats whats popping up in my head, also they were specially made ovens for pizzas with little doors to slide the pizzas in and out. I'm sure those real pizzarias know whats best though and do it right but and also have the best tasting pizzas with the freshest ingredients but as with everything, there is always more than one way to cook a pizza. Well enjoy your pizza!

Oh man all this pizza talk is making me crave pizza especially at a pizzaria!! Where are the yellow pages!

[Johnny GUitar]

delete ot

Edited August 16, 2005 by Johnny GUitar

[rhoads56]

BTW, there must have been a method for straightening necks before these neck heating jigs became somewhat common (I bet they were hard to come by before the 60s/70s), I wonder what they did in those days, eh?

John

←

They used heat lamps, above the fretboard, if you must know.

I actually want to see you chuck this rare bird in the oven and destroy it. Please take photos.

Edited August 16, 2005 by rhoads56

[Southpa]

Many years ago I used to do it for a living (cooking pizzas, not guitars ). Used one of those conveyor belt ovens, temp was 650 deg. and it thoroughly cooked a pizza in about 10 minutes.

BTW, there must have been a method for straightening necks before these neck heating jigs became somewhat common (I bet they were hard to come by before the 60s/70s), I wonder what they did in those days, eh?

In the early days they used to straighten warped/bowed necks with a small alcohol lamp, wooden blocks and clamps. I sent you a PM Johnny G.

[rhoads56]

Wes is right.

Any more off topic chit chat can be posted in the off topics section. Dont make me delete your posts.