Help w/ compression fretting - or somethin'

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Help w/ compression fretting - or somethin'

Postby Mark Wybierala » Tue Jul 24, 2012 2:06 pm

In front of me is an absolutely perfect Fender 12 string stratocaster. When I first went to adjust the trussrod at the heel, the nut was about 1/8" recessed into the end of the neck which is not typical and a warning that something may be amiss. I have a range of spacers and shim washers from McMasterCarr for situations like this so I installed a single spacer and brought the trussrod nut contact point to being flush with the end of the heel via six full revolutions (adequate thread engagement). Through adjustment and tuning to pitch and readjustment... - I found that the force required to adjust the neck was quite a bit more than typical -- adjustments were done with the neck unstrung and at one point, I had an assistant inflict forceful backbow in the neck while I adjusted the trussrod nut. I was able to get the neck flat under string tension. I then performed a fret level due to three significantly elevated frets restrung the guitar with new strings and it set up and played wonderfully.

The next day I returned to the bench to find that an excessive amount of relief had returned. I believe that If I adjust the trussrod again, the nut, or maybe even the anchor on the other end will probably sink and the relief return. Excessive torque is needed and there is a danger of the trussrod breaking. Unstrung, and with the trussrod nut completely removed, there is nearly 13/32" of relief. Comparatively speaking, the neck is noticeably more ridgid than many of the fender necks I encounter. It is this forward warp that is causing the trussrod to work too hard and this is also a twelve string. Unless I build a new neck (I don't wanna) I'm not going to find a replacement neck let alone one with the correct decals and serial number which significantly establish the value of this instrument.

I'm thinking about attempting a repair via compression fretting which until now I have only ever done accidentally. The existing relief curve is fairly uniform. The fretboard is rosewood

I'm looking for suggestions for what I will use to fill the existing fret slots. I'm thing about starting with water-thin CA to seal the end-grain of the rosewood in the slots and then either heavier CA applications done over the course of a few days or using donor wood bonded in place via CA.

I have a fret slotting saw that I got from Stewmac a few years ago that has always cut slots at .020 max. I was going to return it but never got around to it. I can establish new slots starts using traditional methods and then cut the slots to full depth with the neck forced into back bow. I probably could install the frets with the neck forced into backbow at intervals of every forth fret and check the untensioned relief between intervals.

Thoughts and suggestions please.
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Re: Help w/ compression fretting - or somethin'

Postby John Hamlett » Tue Jul 24, 2012 3:18 pm

I have a couple of different fret wires with tangs that are around .022" to .024" thick. Got them by accident (that's the tang itself, the "bumps" not included). I think you'd be better off forcing wider fret tangs into the slots than trying to build up the slots, but even so, I've not had very good luck (long term) with compression fretting, so I don't have a lot of confidence in it working well in this case. (Perhaps we'll hear from others who have had better success...)
My recommendation to the customer would be adding some CF to the inside of the neck, which of coarse means popping the fingerboard off and inlaying the CF. If that's too much expense, he/she had probably better learn to like a lot of fingerboard relief.

Or, you could talk him/her into bar frets. You can backbow that neck all you want with those things!
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Re: Help w/ compression fretting - or somethin'

Postby Rodger Knox » Tue Jul 24, 2012 3:30 pm

I'd be tempted to try to get rid of the untensioned relief using heat. With that much untensioned relief, I suspect that at some point in it's life, the guitar was in a heated environment under string tension for some period of time, causing the fingerboard glue to soften and creep. I'd clamp it up with a little backbow and heat the fingerboard enough to soften the glue. Repeat several times if necessary.
If that doesn't work, you can pull the fingerboard, repair or replace the trussrod, and straighten/flatten the neck as much as possible. If you can't get the neck straight, you could also use a curved caul to induce a little backbow into the neck when you glue on the fingerboard. Using Titebond 1 for reglueing the fingerboard might also be a reasonable idea, the moisture would help in this situation.
There's a pretty good article by John Hall on compression fretting in a recent Guitarmaker if you decide that's appropriate.
A man hears what he wants to hear, and disreguards the rest. Paul Simon
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Re: Help w/ compression fretting - or somethin'

Postby John Hamlett » Tue Jul 24, 2012 6:17 pm

I didn't recommend heat setting because I've not had good, permanent results from that either, and of the others that I know who have done lots of them, only a percentage of those necks are improved long term.
Also, Titebond can cold creep, hot hide glue does not. If the board were to be removed and re-glued, I'd recommend hot hide glue, but if the fingerboard is coming off anyway, a Cf stiffener can be installed to fix the problem.
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Re: Help w/ compression fretting - or somethin'

Postby Mark Wybierala » Tue Jul 24, 2012 8:31 pm

I have a jig for torturing necks under heat and I've had success but only with relatively new necks from China. On top of that, my success has been limited to pushing neck in the opposite direction. The repairs have been permanent but I also consider that the necks are getting help from string tension. I this case, the opposite applies and I don't have much faith in the heat. Fretwork is my forte so I'd like to stick on the most familiar path. This guitar belongs to the business so all of the expense is on me.
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Re: Help w/ compression fretting - or somethin'

Postby Michael Lewis » Wed Jul 25, 2012 1:14 am

Mark, I think you are going to get some education from this one. Go ahead and try the fretting approach, and if it doesn't work then remove the fingerboard and the truss rod to find our what the problem really is, and repair the compressed wood at the end(s) of the rod. Obviously it should not require so much force on the rod.

StewMac sells a fret tang expander, makes the tang zig zag to enlarge it in the slot for just such occasions. I have one, don't use it much, but there are times it comes in very handy.
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Re: Help w/ compression fretting - or somethin'

Postby Mark Wybierala » Wed Jul 25, 2012 11:11 am

Education is scary but education just happens doesn't it. As things are, the guitar is unplayable within reason. Its relatively rare; I personally feel its very desireable because its flawless and unique (emotional irrationality); but it actually does not command a premium value -- darn-it. I'll do the fretwork simply because I know that I can do this cleanly. But if it proceeds to removing the fretboard, I don't know how these neck were manufactured in Japan and whether or not the trussrod is installed in the same manner as with solid maple necks or not. If they are, there will still be no full access to the trussrod or its anchor points. Come to think of it, I don't recall if there is a skunk stripe on the back or not. The neck is at work. If there is no skunk stripe, things will be looking up. Thanks everyone.
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Re: Help w/ compression fretting - or somethin'

Postby Mario Proulx » Wed Jul 25, 2012 11:35 am

The StewMac tool won't help here; it's great for worn-out fret slots, but it doesn't add much compression.

If wider tang fretwire is hard to find, make thin shims of ebony or a dense rosewood(to match the fretboard) using a plane, glue these into the slots, and fret as usual. It would help if you make a jig of some sort to hold the neck in a forced, but slight, backbow when you're fretting, also.

Just out of curiosity, you're not tuning it to standard pitch, with a "standard 12 string set" of strings, are you? 12 strings are typically acoustic guitars, and the string sets are usually pretty heavy, and none are really meant to be tuned to full concert pitch, but rather, one full step(2 frets) lower. That might be the cause of the problem right there...
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Re: Help w/ compression fretting - or somethin'

Postby Ron Belanger » Thu Jul 26, 2012 11:42 am

What Mario said
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Re: Help w/ compression fretting - or somethin'

Postby Michael Lewis » Sat Jul 28, 2012 2:05 am

Everyone has their own approach to the workings of instruments, the fret expander has worked for me. Compression fretting has it's limits, not always a wonderful process or results, but if you do enough little things to help it along they can add up to success.
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Re: Help w/ compression fretting - or somethin'

Postby Mario Proulx » Sat Jul 28, 2012 8:03 am

but if you do enough little things to help it along they can add up to success.

That, right there, sums-up everything we do, actually. Much too often, there's not any -one- fix, but rather a combination of many little ones aimed at the goal.

Thanks for reminding us, Michael!
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Re: Help w/ compression fretting - or somethin'

Postby Mark Wybierala » Thu Aug 02, 2012 8:52 am

lmii sells a fretwire that is specified to have a tang width of .024. I don't have any on hand and I make it a point of keeping a large quantity and range of fretwire in stock so I'm going to order some and give it a try. This is an early 1980s MIJ so the rosewood is of what I consider to be high quality rosewood for a Fender. The .024 is .002 - .003" per fret wider than the original MIJ wire so .002 times 21 is a .040" impact toward the idea of compression. I'm going to begin with heat and hopefully let the fretboard creap slightly with the neck tensioned into an exagerated backbow. I'll then do a fretting of every other fret and see if I actually get any satisfaction toward the reduction of the non-tensioned relief or forward bow. Hopefully again, the heat has let the fretboard creap and has resulted in a slight widening of the fret slots. The slots consistently measure a very snug .022 currently. It is not fun hammering frets into slots that are undersized. The nice thing here is that we are dealing with a Fender neck that probably is one of the strongest most abusable necks made. I can really crank up a lot of induced backbow without any danger of causing a fracture even while hammering frets. Like I mentioned earlier, This neck is compatively quite a ridgid one.

I can't detach myself from my endearment to this instrument despite its oddly limited value so I'm looking at this as a payment for the education that was mentioned earlier. Its an indulgence actually but the education aspect of the adventure is my official excuse and I'm sure that there are others who can relate.
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Re: Help w/ compression fretting - or somethin'

Postby Barry Daniels » Thu Aug 02, 2012 10:00 am

I forget who it was that posted a technique a few months ago about repairing a neck by placing the neck into a slight back bow and applying thin CA glue to the frets allowing it to seep into the slots. After the glue was set it kept the neck from bending forward. They claimed that the repair was more permanent than a heat set. One good thing about the technique is that it should do no harm to the instrument.
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Re: Help w/ compression fretting - or somethin'

Postby Mark Wybierala » Tue Aug 07, 2012 9:10 am

I often get my hands on lost cause guitars. I strip them down for anything that is valuable and sometimes this includes sections of the top, back or sides of an acoustic and certainly all of the the hardware on an electric. I'm going to try this bent back neck and superglue idea on something. I often use CA for spongy frets and cleaning up aftwards on rosewood is relatively simple. I should receive my fretwire today or tomorrow from LMI. I also ordered .024 thick rosewood strips if I end up filling in the existing slots and re-cutting them. My only concern with CA and fretwork is tearout when I someday might pull the frets. I suppose heat from a soldering gun would help.
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Re: Help w/ compression fretting - or somethin'

Postby Mario Proulx » Tue Aug 07, 2012 10:37 am

Yes, heating the frets before pulling them will avoid any tearout. It's good practice to do so on any fret job, in fact...
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Re: Help w/ compression fretting - or somethin'

Postby Mark Wybierala » Tue Aug 14, 2012 10:28 am

I did the compression fretting and it absolutely didn't help at all.
Here is what I did: I made a simple stessing jig that put the neck into a fair severe backbow with the heel secured flat in one end and the headstock clamped downward in a rigid manner to a stop block that was solid to the jig. The trussrod nut was removed during this process. I applied heat to the fretboard for about an hour with a heat gun getting the fretboard really hot. AT this point, the frets were still installed -- my thought was that the frets would help to transfer heat deeper and faster. When I was done applying the heat, I pulled the original frets which came out easier than any frets I have ever pulled before. The frets at the heel remained in place because the neck was still in the stressing jig, under a caul and the neck was still bent into a back bow. I let the neck cool for five hours in the back bowed position. I then installed the new frets with their wider tang of .024 and I did verify that the tangs were to spec. The original frets all measured .021-.022. I installed the new frets from #1 to #15. They hammed into place with no difficulty. The new frets left a gap of about .020 below their tangs due to the depth of the slots. While still clamped in the original backbow, I wicked in water-thin CA into these small holes under the fret tangs from one side of the neck and then the other alternating back and forth until the the holes would not take anymore CA. I let the neck sit for 24 hours and during all this time it remained in the original clamped backbow condition. When I removed the neck from the jig, the excessive forward bow returned.

Later that day, I pulled all of the frets and planned off the fretboard on a joiner. I was able to plane away the entire rosewood fretboard to an ovoid shape about 4 inches long and one inch wide in the center of the neck. The maple that was planed away on the far ends was not deep enough to encounter either the trussrod anchor at the headstock end or the heel adjustment hole. The existing surface is quite flat and I feel quite lucky considering that the permanent forward bow was about 1/8" of unstrung relief. I was ready to grind with my dremel if I need to take off more.

For those who are interested in Fenders, I made a small discovery while doing this. As I was going to remove the fretboard, I thought that it was a good idea to mark the positions of the 12th fret and the nut face. It was only by accident that I actually measured this distance and discovered that the distance was 12-3/8 instead of the anticipated 12-3/4. The early '80s Stratocaster XII has a scale length of 24 3/4 instead of 25-1/2 which is often cited incorrectly in reviews and specifications on the internet. I only found one obscure article which described this correctly and many others were wrong. This was a lucky discovery because I very nearly ordered the incorrect scale length for my replacement fretboard from LMI. I would have had a very confusing situation on my hands.
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