I have a walden guitar which has a truss rod. It's action was high and I gave it to a music shop to adjust. They adjusted the neck but now the frets are buzzing a bit. Also I think that the action could have been adjusted by reducing the saddle height and I'm thinking of doing it myself.

When I check at ebay there are different kinds of truss rod wrenches and in different sizes (4mm/5mm). How do I decide what to buy? Can someone tell me based on my guitar?

  • 8
    A comment rather than an answer. If you've paid for a job and it's not right, take it back. While there, ask what size tool is needed.
    – Tim
    Jul 29, 2014 at 8:49
  • ...a truss rod on a classical guitar? :-o Mar 23, 2015 at 22:31

4 Answers 4


Well, you have two choices I guess.

1) Use a pair of calipers to determine the precise size wrench needed for the specific guitar you own right now. Or find out through some other means (e.g., by contacting the manufacturer and asking what wrench size is needed).

2) Buy a multitool which will have the right size for now and also probably for any other future guitar you could ever own, and never have this problem again. here's one example of a guitar multi-tool, though probably a bit more specialized than you need.

  • 1
    One consideration for multi-tools is that the body of the tool -- which is large enough to accommodate the other bits -- may interfere with nearby material. In particular, I imagining either the soundhole or the headstock. In these cases, a "skinny" tool may give you the best range of motion. The classical guitar identified by your link may not have a truss rod, but if there is one, you will be able to access it via the soundhole. Get a small mirror on a stalk to inspect the inside of the body for evidence of a truss rod. Good luck!
    – Kirk A
    Jul 29, 2014 at 11:15

Your guitar appears to be a nylon-strung classical guitar, and as such may not have a truss rod.

However, it's worth going on to answer the question in general:

Unless you have a very unusual guitar, a truss rod tool is either a hex key or a hex socket. These are common fittings in all kinds of fields, not just musical instruments: bikes, self-assembly furniture, etc.

Paying $7 for a tool you're not sure will fit, seems silly when discount shops (and eBay) frequently have socket sets, or bundles of hex tools, for cheaper.

The only slight issue with this approach, is that some sets are metric, some imperial. Worst case scenario, you get a cheap tool that's no use for your guitar but will be useful in other ways for the rest of your life!

The manufacturer should be able to tell you the right size, if Google can't.

  • 3
    Once the inside of an Allen bolt is rounded, the truss-rod is unadjustable. It's also easy to round off an external hex with an 'it might just fit' tool. Been there, done it ! Make certain it's exactly right.
    – Tim
    Jul 29, 2014 at 12:05

Go down to your local hardware store and try various hex wrenches until you find the one that fits snugly. Then buy it there. Buy local.


Different guitar builders use different size truss rods and you need the specific type wrench and exact size for your guitar. Some truss rods are adjusted with a socket wrench while others use an allen wrench and others may use different type wrenches.

Under no circumstances should you ever attempt to use the wrong size truss rod wrench or you could strip the nut or socket and then you will never be able to adjust the truss rod again.

To find out what type and size wrench you need for your guitar, call Walden Guitars.

Walden Guitar USA information line (9am-5pm EST): 1-888-925-3369.

Then go to your local hardware store and purchase the specified wrench.

Also -unless your particular model Walden Guitar has an adjustable saddle, you will have probably have to sand the existing saddle down to lower the height should you choose to do so in an attempt to further lower your action.

Before attempting to file down your saddle by using fine grit sandpaper on a hard flat surface, obtain a spare saddle that is an exact match of your current saddle. If Walden won't sell you the part, try AllParts.com Guitar saddles on-line.

By having a spare, you can start over if you end up sanding it down too much. You can put a shim under it to raise it back, but it's better not to have a shim if you can avoid it.

Good luck.

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