Truss Rod Inspection

With the fingerboard removed, I can see exactly what the problem is. The end of the round threaded bar in the following photo should extend about another inch - this is the point where it has snapped off.

There should then be a threaded nut, something like this picture below, attached to the end.

This is where the allen key fits to adjust the rod. Prising out the rod was easy - it sits in a well machined slot, but isn't glued in.

This next picture shows really clearly where the threaded portion snapped.

The rod can be pulled out from the channel. It's an interference fit at the top end that stops it rotating when tightened.

As a quick aside, the small piece of bar that you can see left in the truss rod channel is fundamental to how the truss rod works. It means that, when the threaded rod is inserted in the channel, it actually has a curve set into it. When you then tighten the threaded rod, it is essentially being shortened and wants to straighten out, so the truss rod channel takes on the curve instead (in the opposite direction) and transmits that curved shape to the neck because it is fixed in place. 

So I think I have a couple of options now:

1. buy a new truss rod of matching length etc. I might need to machine out the slot a little or pack it out for the new one to fit, or
2. repair the existing rod by having a new piece of 5mm rod welded to the existing and cutting a new thread, and buy a new nut for the end.

Option 2 is probably my preferred option, depending on how much it will cost to do. 

Actually, there might be a third option, which would be to totally remake the threaded rod - heat the top and belt it "blacksmith fashion" to make a mushroom shaped head on it and then cut a thread myself. That is quite appealing 😃. Watch this space ...

Time for some ironing

I've done plenty of research on Google / You Tube etc and there is a fairly good concensus of how to do this job. Get some heat into the neck to melt the glue and then use a blade to "lever" the fingerboard and neck apart. Off we go then - how hard can it be?

First action, after removing the strings, was to remove the nut. Not too difficult - there is normally (in my experience of 3 projects!) only a small amount of glue just locating the nut. Using a block of wood and a couple of gentle taps with a hammer it soon came away. 

Some methods have you now removing a fret at each end of the fingerboard and drilling a small hole through the fret slot and into the neck, allowing you to use a couple of panel pins to positively locate the fingerboard back into the exact same position when re-glueing. I'm not doing that as I think I'd be more likely to damage the fingerboard removing the frets, so I'm going to rely on clamping side to side as well as down to the neck.

Now the slightly scary bit where the iron comes out! The idea is to use the iron to transfer heat into the neck by resting on the frets, which will conduct the heat into the joint. I have seen one suggestion to use a metal ruler between the iron and frets, which I guess would add some protection to the wood surface, but I thought I'd prefer to get the heat directly onto the frets. As it was, the upward bend in the neck meant that the iron probably wasn't actually in contact with a lot of the frets. 

I set the iron to high and with a bit of steam as well. Starting from the nut end, I left the iron balanced there for about 10 minutes.

The next stage needs a blade to prise open the joint. You can get various specialist "pallette" knives etc from luthiery suppliers. No doubt they would be the right thing to use on good quality work. For this project I just got two good quality Harris 2" decorating scrapers from a DIY store - one with a sharpened edge and one with a blunt edge. Very carefully, I prised apart the joint - it actually needed a really gentle tap with a small hammer to get going. 

Once the joint had started to open, I got some more heat on for a minute or two and then slid the blunt scraper in sideways under the sharpened scraper. Then, being very patient, it was a matter of working the blunt scraper down the neck a bit; applying more heat for a couple of minutes; and then prising the joint open a little more by using the sharp scraper between the blunt one and the fingerboard. It probably went at a rate of about an inch a minute?

I forgot to mention earlier that I taped up the finish on the body where it was going to be exposed to the blades and heat from the guitar, to try and protect it as best as possible. The next picture shows the way I used the 2 scapers well.

As I worked my way down towards the soundhole end, you could see a distinct upward set in the fingerboard. I'm not sure whether this was the heat and steam doing this, but fairly confident it would glue back OK. Just to be on the safe side, after removal I clamped the fingerboard to my workbench to dry out flat.

As I got to the part where the fingerboard is glued to the body, there were a couple of ominous "cracks", as the joint gave way, and then it just suddenly popped off.

The cracking noise was a small part of the paint finish parting company with the body - you can see the blue paint left on the underside of the fingerboard below. Not the end of the world - it is only about 1mm of visible paint at the junction. As a learning experience, I would carefully score down the junction between fingerboard and body with a sharp craft knife next time, which should avoid this happening again.

I was pleased to see how clean the joint surfaces were, with no wood broken away on either. They'll clean up really easily to reglue.

Next Project - Fingerboard removal and truss rod repair

I bought this Applause AE28 electro-acoustic off EBay over a year ago. It is in pretty much brand new condition, hardly played and cost me less than £30. They weren't a particularly expensive guitar when new; less than £200 I think and can be found second hand for less than £100. 

Applause is Ovation's budget brand. It follows the Ovation build practice of having a round ABS (I think) back, and is bonded to a spruce top (not solid top). There is nothing particularly elegant about it and they sound a bit weedy unplugged, but allegedly better when plugged in. 

So why was it so cheap? The original owner was an electric guitar player and used to a very low action. He was trying to get the action very low by adjusting the truss rod. He overdid it and "twang" the truss rod snapped! So the neck has no tension in it and the action is really high, particularly on the nut end - you can see the upward bend on the neck in this photo. 

There should be an adjusting nut accessible through the soundhole (you can just see the access hole in the spruce inner bracing below the bottom of the fingerboard in this next photo) but it's what snapped off, so not there.

Why go to the effort of repairing this guitar? To fix it, I'll need to remove and replace the fingerboard (to get access to the truss rod). On my previous project (the Faith neck repair)  I had originally thought that I would need to remove the fingerboard to do the neck repair, and I wanted to try first on a cheap guitar that I wouldn't be precious about if I damaged it or it went wrong. So I bought this as the practice project. As it happens, I didn't need to take the fingerboard off on the Faith, so this project was sidelined.

However, the Faith project wasn't wholly successful and I need to do some further work on the neck joint, which means removing the fingerboard, so this project is back on the table as a practice. If I can fix it, it will go to a good home as a decent beginner guitar for someone.

So the plan of action is to:

• remove the strings
• remove the nut to give access to the joint between neck and fingerboard
• remove the fingerboard
• fix or replace the trussrod
• prepare neck and fingerboard for reuse
• reglue fingerboard
• reglue nut
• new strings, set up and play!