Scary Neck Repairs: Two Wal Necks

[Bruce Johnson]

Wow, so the original Wal neck had a rod that was just soldered to the anchor block, whereas your repair, with the new threaded anchor block, will be "screwed in" nice and tight. Sounds like a great plan.

Yes, threading is the strongest, most reliable way to attach a truss rod to an anchor, particularly if they are two different metals. Here's an example of another custom truss rod replacement that I did a few years ago. I was replacing a broken truss rod on a very rare Japanese Fender Lyte neck.

In this case, I machined the anchor from stainless.....It was a strange shaped anchor.

The rod is also stainless, threaded. Some Red Loctite applied.

And there it is. It's on there for good. The threads take all the tension load; the Loctite is there just to prevent it from unscrewing inside the neck.

If the anchor looks like it's on the rod a little bit crooked, that's because it is. The threaded hole is drilled through the anchor at a 2 degree angle, to get the geometry of the rod right.

This is what I'll be doing on Alex's Wal, except the anchor will be a rectangular brass block. I'll size it to fit into the existing pocket in the neck, after I clean it up a bit.

The 4mm die is supposed to be arriving Tuesday. The West African ebony fingerboard showed up today.

 

[zuma]

Not just screwed together, also glued with red Loctite which, in this case, is as strong as a weld; as the rod will snap long before it breaks the Loctite bond.

Ahhh yes, the Loctite as well. That's some good stuff.

 

[Lo-E]

I've done a similar anchor repair to a '71 Strat. In my case the rod hadn't broken, it had just unthreaded itself from the anchor and couldn't be coaxed back in from the heel end.

I didn't want to sacrifice the original fingerboard so I pulled the first fret and the nut and, using a narrow piece of saw blade, sawed two short slots on either side of the first piece of fiingerboard; one in the bottom of the first fret slot and one on the leading edge of the nut slot. Each cut was about 3/4" long and centered on the fingerboard. Then I took a beater chisel and pried the fingerboard up between the cuts, allowing it to split along the grain and lift up. I then had access to the anchor and was able to thread the rod back in (with locktite). This sounds really barbaric, but no material is lost in the exposed part of the board and when glued back up the repair is completely invisible. The saw cuts in the fret slot and nut slot were patched with sawdust and glue and covered by the new nut and the replaced fret. It's a very clean way to access the rod anchor without losing the entire board.

It's a trick I was taught by Matt Brewster at 30th Street Guitars in Manhattan. He could have charged me a lot to do the same repair but, instead, he explained how I could do it myself. A real stand-up guy.

I'll level the frets with the truss rod tightened up to maybe 40%. That should give it a good working range for adjusting the relief.

This one has me scratching my head a little, Bruce. Isn't 40% a lot? I typically dress frets with the rod just slightly engaged (assuming the board is flat when the rod is relaxed) so as to maximize the tightening range of the rod if needed. I could see going a little further to allow some adjustment in the other direction in case of super light strings but isn't 40% overkill?

 

[Bruce Johnson]

This one has me scratching my head a little, Bruce. Isn't 40% a lot? I typically dress frets with the rod just slightly engaged (assuming the board is flat when the rod is relaxed) so as to maximize the tightening range of the rod if needed. I could see going a little further to allow some adjustment in the other direction in case of super light strings but isn't 40% overkill?

On new necks that I build, I pre-tighten the truss rod to 50%-60% before cutting the surface of the fingerboard to straight. I leave the truss rod like that through the rest of the build, installing and leveling the frets, etc. So the neck is straight with the truss rod about half-tight and no strings. When the strings are on and pulled up to tension, the neck will pull forward into a small amount of relief curve. If I've done my engineering and construction well, that relief curve should be about the right depth and shape. I should only need to make a small adjustment +/- to the truss rod to bring the relief right to where I want it.

The point is that, at full tension playing condition, I want the truss rod to be about halfway tight. That greatly improves the stability of the neck, keeping it from moving with the weather. And it also improves the overall sound of the bass, which is another topic that gets argued regularly.

On this Wal neck, I know that it has already shown to be a little soft, and had a small extra forward bow. So, I'm going to do the fret leveling with the truss rod at around 40% to give it a little extra range. I'm expecting that I may have to take it up to 50% under string load, to get the relief right. That's what I want.

 

[Chickenwheels]

I've got the internet sort-of patched. Here's what I did to the truss rod on Mike's Wal neck:

View attachment 5169658

This is what the truss rod nut looked like as it arrived here. The nut is sunken in about 0.140" from the end surface of the heel. And it tightens up real hard, as if the threads have run out of travel. Hmmm.....Why?

View attachment 5169659

I had no trouble loosening the nut all the way, and taking it out. These three little steel washers shook out. Mike said that he had put in some washers, to see if it would help. I assume that's what these are.

So, why is the nut running out of threads? I took some careful measurements and determined that, yes indeed, the end of the truss rod was jamming up inside the nut. The good news is that the threads on the truss rod are in good shape, there's plenty of them, and it didn't appear that the rod is pulling out of the neck.

The problem is that the nut is going in too far. The back shoulder of the nut is going back farther than it should before it contacts something solid to push against. And, looking down inside, that appears to be a metal surface, the rear anchor block. It doesn't look like anything was crushed in, or could be crushed in.

Everything looks fine, except it needs a thick spacer/washer to bring the nut out farther. Where it will have plenty of threads and travel distance.

What happened to that spacer? Did Wal forget to put it in because this was a rush-rush trade show bass? Somewhere along the line, did someone take the nut out, drop out the spacer, and not put it back in?

I dunno.

View attachment 5169660

Whatever. I took good measurements of what the spacer should be.....

View attachment 5169661

....And quickly machined one up on my Logan lathe from a chunk of brass bar stock. It took about 5 minutes.

View attachment 5169662

And there's the new brass spacer and the nut. I put a little grease inside the nut and put it back together.

View attachment 5169663

And now the nut is flush with the heel, like I think it should be. There's plenty of engagement of the threads, and plenty of travel. I tightened it up and it seems to work just fine. I took it up to maybe 70% and was able to backbow the neck about 0.060". That's about right. That should give the truss rod enough travel to handle the working range.

View attachment 5169664

With the truss rod at maybe 20%, the neck is almost dead straight, sighting down the glue line between the neck and fingerboard. The neck itself doesn't have any real warpage problem and the truss rod is functioning. It's healthy.

The only problem now is that there's a small lump and dip thing in the fingerboard surface down near the 3rd-5th fret area. I don't know whether this was from the factory, or the fingerboard wood did that by itself as it dried out.

But it's not much, and the frets are pretty low on this neck. So, next up, I'm going to pull the frets carefully and do a light block leveling of the fingerboard surface. Taking off as little wood as I can, probably about 0.010". Then refret it with small size stainless wire. Then I'll level the frets with the truss rod tightened up to maybe 40%. That should give it a good working range for adjusting the relief.

And I think that's all this neck will need. A pretty simple repair, actually.

Very enjoyable thread this, thank you!
I did this exact procedure with the spacer on my Roscoe Beck V and it worked a charm.

 

[zuma]

Excellent info. You should write a book @Bruce Johnson ! I'd purchase it.

 

[J Wilson]

All I can say is it isn't Scary Repairs watching a Professional at work. Thanks for letting us look over your shoulder Bruce, and all the insights along the way.

But I did have a question: Why do you rout off the old fingerboard instead of removing it (steam, heat, etc.) in one piece off the neck? I understand it processes the new surface for the new fingerboard to dead, West Texas straight. I'm guessing simply sweating off the old fingerboard would leave you with still having to level the mounting face for the new fingerboard?

Again, Thanks.

 

[stevensivak]

Wonderful explanation and photos!
Two questions:
1. The wooden shoulder that the heel nut compresses against is minute! Under tension, can't that shoulder fail to support the tension placed upon it from the rod?
2. Not to be critical, but I noticed in your fingerboard repair from the earlier Wal, your fingerboard was only the width of the neck. If you look closely at the photos in post no. 1, you can see the two small triangles of maple at then end of the neck that did not get the fingerboard material to cover. Very nit picky of me, but I am sure you are aware of this. What will you do to address this issue this time around?

 

[Bruce Johnson]

Excellent info. You should write a book @Bruce Johnson ! I'd purchase it.

Thanks! I've been writing threads like this here on TalkBass since about 2010. There's a whole book full of them if you look around. And they're free!

 

[zuma]

10-4 Bruce. Thank you for your contributions!

 

[Bruce Johnson]

All I can say is it isn't Scary Repairs watching a Professional at work. Thanks for letting us look over your shoulder Bruce, and all the insights along the way.

But I did have a question: Why do you rout off the old fingerboard instead of removing it (steam, heat, etc.) in one piece off the neck? I understand it processes the new surface for the new fingerboard to dead, West Texas straight. I'm guessing simply sweating off the old fingerboard would leave you with still having to level the mounting face for the new fingerboard?

Again, Thanks.

Hey J Wilson;

In my experience, it just isn't worth the trouble to take a fingerboard off using heat. That works on acoustic guitars and some classic electric guitars, but the fingerboards on most electric basses are too thin. Bass fingerboards will almost always break apart at the fret slots, or crack, or curl up when you slice them loose with heat. Rarely can you use them again. The process takes a lot of time, and there's still a lot of cleanup afterward. I've done it successfully a few times, when the fingerboard was particularly valuable.

A couple of years ago, I tried to make up a special heat knife just for the purpose of removing fingerboards. Nichrome wire with a thin stainless blade right behind it. I thought it might make the process more reasonable. But it didn't work. I fought with it for a while and gave up on it. The parts are stashed away in a box. Maybe someday I'll make another attempt at it.

Routing the fingerboard off is fast and simple, if you have the fixture. I spent maybe 20 minutes on this Wal neck, and I was going slowly and carefully. In most cases I can rout off a fingerboard in 10 minutes.

 

[Bruce Johnson]

Wonderful explanation and photos!
Two questions:
1. The wooden shoulder that the heel nut compresses against is minute! Under tension, can't that shoulder fail to support the tension placed upon it from the rod?
2. Not to be critical, but I noticed in your fingerboard repair from the earlier Wal, your fingerboard was only the width of the neck. If you look closely at the photos in post no. 1, you can see the two small triangles of maple at then end of the neck that did not get the fingerboard material to cover. Very nit picky of me, but I am sure you are aware of this. What will you do to address this issue this time around?

Hello Steven;

The inner end of the truss rod nut on these Wals doesn't press against wood. It contacts right against the heel-end anchor block, which I think is aluminum. It's embedded in the neck about an inch from the heel. The truss rod slides through a hole in it. The problem with Mike's neck was that there needed to be a spacer, about 0.140" thick, between the nut and the anchor. If you threaded the nut on the rod far enough that it contacted the anchor, the end of the rod would jam up inside the nut. Everything was fine once I put the spacer in there. I don't know why the spacer was missing.

I don't remember all the details of that Wal neck that I repaired in 2010. But I think the trim of the end of the fingerboard was done to match the way it was. Now, that neck was a more complicated job, because it had a fairly severe twist. I had to machine down the top surface of the lamination a bit to get it straightened out. I think that's what created those two little flat triangular spots. In that picture, the repair job wasn't done. I believe I blended those spots and touched up the finish.

On Alex's Wal, I'll fit and trim the end of the fingerboard to match the way it was. The new fingerboard will be ebony, at the original 12" radius, and a little thicker.

 

[J Wilson]

Hey J Wilson;

In my experience, it just isn't worth the trouble to take a fingerboard off using heat. That works on acoustic guitars and some classic electric guitars, but the fingerboards on most electric basses are too thin. Bass fingerboards will almost always break apart at the fret slots, or crack, or curl up when you slice them loose with heat. Rarely can you use them again. The process takes a lot of time, and there's still a lot of cleanup afterward. I've done it successfully a few times, when the fingerboard was particularly valuable.

A couple of years ago, I tried to make up a special heat knife just for the purpose of removing fingerboards. Nichrome wire with a thin stainless blade right behind it. I thought it might make the process more reasonable. But it didn't work. I fought with it for a while and gave up on it. The parts are stashed away in a box. Maybe someday I'll make another attempt at it.

Routing the fingerboard off is fast and simple, if you have the fixture. I spent maybe 20 minutes on this Wal neck, and I was going slowly and carefully. In most cases I can rout off a fingerboard in 10 minutes.

Thanks, Bruce.

All the Best,

JW

 

[stevensivak]

thanks for the reply. But it looks like, for example, that a 1-1/2" neck needs a 1-3/4" fingerboard in order to cover the "bell-bottom" at the nut?

 

[sissy kathy]

thanks for the reply. But it looks like, for example, that a 1-1/2" neck needs a 1-3/4" fingerboard in order to cover the "bell-bottom" at the neck?

Those dimensions are undersize, but you are correct. When the lumber for the fingerboard is ordered it is usually a trapezoid for just that reason.

 

[zuma]

Fascinating, I'll have to look at all my basses when I get home and look for these shapes. I didn't think they flared out at the headstock like that.

 

[sissy kathy]

Fascinating, I'll have to look at all my basses when I get home and look for these shapes. I didn't think they flared out at the headstock like that.

That depends on the manufacturer. Fender finger/fret boards stop at the nut.

 

[Bruce Johnson]

Yes, having the end of the fingerboard flare out is a matter of the design of the instrument. Wal uses a slot-style nut, like a Fender but wider, and the fingerboard extends about 1/2" beyond the zero line. And their headstock shape flares out starting about at the zero line. And they normally trim the end of the fingerboard so it flares out with the headstock shape. Other manufacturers will trim the sides of the fingerboard to straight over the flares. No functional issue that I can think of, just small detail in the design/appearance. The fingerboard is always oversize in width when it's glued on, then it's trimmed to match the neck.

As I said, I don't remember why I trimmed the sides of the fingerboard on that older Wal repair. But I think it was to match the way it was. I do remember that that particular Wal neck was a very early one, from the early '80's.

It was a valuable bass from a collector's point, and the owner was horrified when the neck developed a bad twist. He put it away in a closet for several decades because he assumed that there was no way to fix it. If I remember right, he originally sent me the neck to have me build an exact replica. He was thrilled when I told him that I could fix the original neck.

Here's why the neck twisted. Wal screwed up in the construction, and glued up the lamination with one strip reversed.

If you want to know more about rings and orientation of rings in laminations and twisting necks, this thread covers it:

About That Quartersawn Maple.....

 

[zombywoof5050]

Looking closer, I can see that the center strip of the neck is itself a lamination of two halves. That's interesting. And there's no filler strip. Most of us install SASR truss rods by routing a curved slot down from the top, and then covering the truss rod with a maple filler strip. Wal apparently routs the curved slot into both sides of those center strips, and then sandwiches the rod between them.

Peavy used to do something like that on their 2-piece necks 30 years ago. I didn't know that Wal was using this design. I wonder why, what's the advantage? I can't think of any right now. But they must have had their reasons.

I'm no luthier, so I hope this is not a dumb question, but when it's done this way, don't you end up with glue squeeze-out in the truss rod channel after glueing the two halves together? And if that's the case, do you just clean it out with something like a big pipe cleaner before the glue dries, or what?

 

[Bruce Johnson]

I'm no luthier, so I hope this is not a dumb question, but when it's done this way, don't you end up with glue squeeze-out in the truss rod channel after glueing the two halves together? And if that's the case, do you just clean it out with something like a big pipe cleaner before the glue dries, or what?

I don't know for sure, but my guess is that Wal glued the halves of the center lamination together with the truss rod parts in there. A close fit, and it's okay if some glue fills in around the rod. Keep it from rattling. Wax the rod before you put it in, and it will crack free and slide within the glue the first time you tighten it up.

If you haven't seen my truss rod installations, that's about what I do, casting the truss rod in a bed of epoxy.