Takamine Truss Rod can it be fixed ?

[Jocelyn Bernier]

Hi,

I need to replace a broken truss rod on a Takamine EG340. Unfortunetly there is nowhere to find one.

It is like a U-Channel but more like a T at the top. Only the rod is broken, I would like to know about anyone who replaced only the rod or replaced it with another type of truss rod.

The rod has thread on one side and kind of round head on the other side.

Anybody can help me on that problem ?

Thank you.

[Freeman Keller]

Do you have the fretboard off and the rod out? If so can you take a picture and measure the channel?

[Jocelyn Bernier]

The fretboard is off. Here is some pictures. The photos are not very good but you might see what I mean.

Length is 14 1/2" for the channel.

Width of the base of the channel is 11mm

Width of the top of the channel is 16mm

Total height is 11mm

Hope this help.

BTW I made a mistake. The model is EG540C.

[Bob Gramann]

Martin used to use a similar rod without the top T. This one has an aluminum channel 14” long and 11mm square. I would guess that the T on the top isn’t really necessary. I have only the one pictured left. It is no longer on Martin’s Guitarmaker Connection website. If you take the broken rod you have to a machine shop, they ought to be able to figure out the hardness of the rod and duplicate it for you. You could then reuse the aluminum channel.

[Bob Gramann]

Another alternative would be to fill the existing slot in the neck with wood, then recut the slot to fit your currently available truss rod of choice.

[Jocelyn Bernier]

5A9091D9-86F5-456F-BD57-79FD2A375205.jpeg

Martin used to use a similar rod without the top T. This one has an aluminum channel 14” long and 11mm square. I would guess that the T on the top isn’t really necessary. I have only the one pictured left. It is no longer on Martin’s Guitarmaker Connection website. If you take the broken rod you have to a machine shop, they ought to be able to figure out the hardness of the rod and duplicate it for you. You could then reuse the aluminum channel.

Going to a machine is my first guess but wanted to see if I could by it somewhere before.

I will have a look at the old Martin one and maybe add some kind of carbon fiber at the top. What do you think ?

Thank you.

[Jocelyn Bernier]

Another alternative would be to fill the existing slot in the neck with wood, then recut the slot to fit your currently available truss rod of choice.

This would be my last attempt

[Jocelyn Bernier]

The other think I can't figure out is why the rod is tied at both end within the channel. That might be the reason why it broke.

If you look at the first and third pictures you will see that both end are press fit so the rod doesn't move.

Could that be bad manufacturing ?

[Bob Gramann]

I would expect that the rod slides in the channel underneath where the channel is pressed to hold it in. You don’t want the rod to rattle-loose in the aluminum channel. By tightening the nut, it bows the aluminum channel (installed with the opening down) and counteracts the string tension. My first guess about why it broke would be that there was some corrosion between the nut and the rod and someone tried to force it. My second guess would be that someone forced it beyond it’s ability to move the neck.

I wouldn’t worry much about using carbon fiber in the fix. Others like it more than I do and might recommend it.

Filling the slot and recutting it to fit a new rod isn’t so hard if you cut the slot first into a board with square edges so you can guide the router and then cut the board, containing the new slot, down to fit the old slot. You can do that as many times as you need to get it right. Personally, I wouldn’t worry about the gaps left by the wings of the T.

Making friends at the machine shop can solve a lot of problems long term.

[Jocelyn Bernier]

I would expect that the rod slides in the channel underneath where the channel is pressed to hold it in. You don’t want the rod to rattle-loose in the aluminum channel. By tightening the nut, it bows the aluminum channel (installed with the opening down) and counteracts the string tension. My first guess about why it broke would be that there was some corrosion between the nut and the rod and someone tried to force it. My second guess would be that someone forced it beyond it’s ability to move the neck.

I wouldn’t worry much about using carbon fiber in the fix. Others like it more than I do and might recommend it.

Filling the slot and recutting it to fit a new rod isn’t so hard if you cut the slot first into a board with square edges so you can guide the router and then cut the board, containing the new slot, down to fit the old slot. You can do that as many times as you need to get it right. Personally, I wouldn’t worry about the gaps left by the wings of the T.

Making friends at the machine shop can solve a lot of problems long term.

Thank you.

I will start by going to a machine shop and see what can be done.

[Bob Gramann]

I just remembered that LMI used to sell a similar rod. So, I looked. Here it is: https://www.lmii.com/truss-rods/6520-tr ... h-162.html

It will probably fit your slot with no modification. You’ll just need to fashion a veneer spacer on the top.

[Jocelyn Bernier]

I just remembered that LMI used to sell a similar rod. So, I looked. Here it is: https://www.lmii.com/truss-rods/6520-tr ... h-162.html

It will probably fit your slot with no modification. You’ll just need to fashion a veneer spacer on the top.

Looking at the measurement it would fit. The length would be too much.

I finally decided to change the rod myself. Bought a 3/16" stell rod, cut it and now I have to thread it.

So far the process is pretty easy.

[David King]

I can thread you a rod and pean the other end or thread both ends for a fixed nut. Threading is quick and painless with the right tools. That's actually a good design but important to figure out why it didn't work the first time. Hopefully you found some better quality steel for the replacement. Stainless 303, 304 and O1 drill rod are all good choices.

[Jocelyn Bernier]

I can thread you a rod and pean the other end or thread both ends for a fixed nut. Threading is quick and painless with the right tools. That's actually a good design but important to figure out why it didn't work the first time. Hopefully you found some better quality steel for the replacement. Stainless 303, 304 and O1 drill rod are all good choices.

Didn't have the time to thread it but got stainless steel so it should work.

I saw the old rod had some corrosion at the thread so I figured that was the cause.

[Bob Gramann]

I have always coated the threads on my truss rods with an automotive anti-seize compound. I found out the hard way that stainless steel requires a special anti-seize compound formultated for stainless steel. Stainless nuts and stainless rids have the abilit to gall against each other and seize. That knowledge has cost me one truss rod replacement so far.

[Jocelyn Bernier]

I have always coated the threads on my truss rods with an automotive anti-seize compound. I found out the hard way that stainless steel requires a special anti-seize compound formultated for stainless steel. Stainless nuts and stainless rids have the abilit to gall against each other and seize. That knowledge has cost me one truss rod replacement so far.

Thank you for the tip

[David King]

A brass nut will avoid galling (microwelds between similar metals due to friction).

[Jocelyn Bernier]

A brass nut will avoid galling (microwelds between similar metals due to friction).

I already put some anti seizing grease but thank you for the tip.