DuPont truss rod location question

cass · July 15

My MD100 has developed a buzz on certain notes and when I tap on the neck I hear a rattle. I’m thinking the truss rod has some play in it and if I give it a slight bit of tension it may help. I have ruled out frets, bridge, tail piece and nut. My neck relief is good. My problem is the hex wrench supplied with the guitar doesn’t seem to reach the nut. I have only tried from the exterior of the guitar. My hand is a bit large to try to fit it and the wrench in the sound hole. I’m afraid I’ll drop the wrench inside. Does anyone have experience with this? Thank you, Jim

jman · July 15

Hi cass,

I have a couple of duponts and have adjusted them quite a bit. You need the long part of the truss rod to push in up close to the top if that makes sense. It can be a bit of a challenge to get it in the hole that’s drilled in the upper traverse brace without damaging the sound hole. Another option which I prefer is to use a long handled ball end Allen wrench of the same size, then put the whole thing in the guitar and spin it around once the truss rod is in place but not yet engaged in the truss rod. I have a small rare earth magnet that really helps with this but I can do it easily with just my fingertips and the strings loosened. To turn you can use something as leverage on the small part of the wrench which should be poking out the sound hole. I use a small piece of aluminium tube. I have had truss rod rattle in other guitars and you should only need to tighten it a tiny bit, less than 1/8th of a turn. Hope this helps.

cass · July 15

Thank you Jman!

I think I need a longer hex wrench. The one I received with the guitar doesn’t have a longer side. It’s approx 3” x 3”.

Gouch · July 15

Your problem could indeed be a rattling truss rod, I’m familiar with the issue. Snugging it (truss rod) up without torquing it either way might help.

The 4mm version of this is the best tool IMO for adjusting a Django axe (4mm is pretty standard, DuPont uses 4mm). Works in an O and a D, no need to cram your hand in the hole.

(Advice: Be ultra-conservative in making truss rod adjustments, 1/4 turn is the absolute max you should turn the truss rod nut, then wait 30 minutes for the neck to absorb the change and try/measure the guitar again).

Tool you want is Item #6212: “For 4mm nut; triple-bend with 5-3/4" reach”:

https://www.stewmac.com/luthier-tools-and-supplies/types-of-tools/wrenches/soundhole-truss-rod-wrenches/?gad_source=1&gad_campaignid=17282679006&gbraid=0AAAAADcBv9gGNa0GcncpjXwTCBKsFZ5-U&gclid=EAIaIQobChMIpcPR27vAjgMVnjcIBR3YkgkKEAQYBSABEgKlV_D_BE

pdg · July 15

It may take a while for the guitar to adjust, if you turn the truss rod nut much. You might have to wait a day to see how the neck -- and body -- respond (the action may change, strings will pull differently on the tailpiece, potentially affecting downward pressure of the bridge on the top),

jman · July 16

https://www.djangobooks.com/forum/discussion/comment/122196#Comment_122196

Here is a photo of the DuPont truss rod wrench next to a standard ball end wrench you can get from a hardware store. Also included the bit of pipe I use on the end for leverage once the wrench is engaged. The length of the long end is 5.5 inch (the part you will need to pass into the hole in the upper traverse brace and then into the truss rod).

While I agree with the above statement for adjusting relief, you should be able to tell if it worked for the rattle instantly. Some rattles cannot be solved this way and will been to be fixed by a luthier, usually by drilling out a fret marker and injecting something into the cavity that houses the rod.

paulmcevoy75 · July 16

If you're not confident with truss rod adjustment it's an excellent one to bring to a (good) luthier. You can do a lot of damage pretty easily.

JasonS · July 16

You shouldn't need to actually adjust the truss rod if the relief is where you want it. You'll know immediately if it is loose to the point of rattling and it won't take much turning to tighten things.

cass · July 16

Thank you everyone for the excellent feedback! I’m glad I asked the question.

Jim

DragonPL · July 22

Have the same issue with my Dupont Favino, must be a Dupont short truss rod thing. I typically tighten the truss rod with that long wrench a bit, and the noise goes away.