Truss Rod Adjustment: Follow up

In the previous post I removed the truss rod plug, added washers, and adjusted the truss rod. But after tightening strings back to tuning pitch it still needed a bit of adjustment. Since the truss rod was already turning hard I decided to try another trick: Apply back-bowing pressure as I turned the truss rod.

There are some pretty cool specialized tools for this job. You can check out Stewart- Mcdonald for those. Because this is a one time deal for me on a $400 guitar I decided to go full on ghetto. This is where I look at my heap of tools and devise a good enough solution.

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What I used: One custom cut length of 2″x4″, two 4″ C-clamps, a shim, 2 other small blocks of wood, and some rags. 4″ clamps barely fit the neck, 2″x4″, and block of wood. If you are buying clamps new get something wider then 4″.

Here are few notes to keep you from destroying your guitar.

  • Take it easy with the clamps. You can very easily bend your neck with this setup. I’ll talk more about this later.
  • Don’t clamp on top of your strings. Take them off or loosen them so they can be pushed off the fretboard. Clamping down the the strings will ruin your strings and possible your frets.
  • Do not clamp directly on the guitar. This will damage the wood. See the block of wood and rag in place? That’s so the clamp doesn’t demolish my fretboard.
  • I’m using a shim here for two reasons.  Shims are soft and about 1.5″ wide. I don’t want to put anything hard with a small surface area against my guitar or it might damage it. Second, shims have varying thickness which makes them easy to adjust for this particular set up.

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Just wanted to throw those points out for the people long on doing and short on reading.

The basic idea is to assist the truss rod as you adjust it. You should be able to get a bit more adjustment out of it and not have that uncomfortable feeling when it turns hard.

It takes a bit of fine tuning to get this set up. For me two drum thrones worked out well. I put on the clamp near the 14th fret first. Not snug but with a little play so I could insert the shim aka fulcrum.

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Then I put on the clamp near the first fret. I adjusted the clamp at the 14th fret so that it grabbed on. Not to tight. Just enough that it would stay in place. Over at the 1st fret there was about 1/4″ between the the back of the neck and the 2″x4″. That’s plenty.  Then I tightened the clamp at the 1st fret just until it started to apply pressure.

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My approach was to sync up with the truss rod and not get ahead of it.  I reasoned that there should be a small clamp adjustment then a small truss rod adjustment and so on. Back bowing the neck too much before the truss rod was adjusted for the bow could strain the truss rod.

Without the strings on this is a guessing game. You can’t know for sure how much concavity the neck has until you tune back up to playing pitch. So after what I guessed to be enough I removed the clamps and tuned up. I got lucky as the adjustment was just right. But I would caution against going too far too fast. Yeah it’s a pain to remove the clamps and tune but it’s a bigger pain to ruin your neck.

FYI your truss rod only effects the first 12 frets so don’t expect it to solve problems above that. It also won’t solve problems with uneven frets. That’s another story and a costly repair at the fret mill.

After the adjustment I took a few measurements to make sure everything was good. I like to use Fender’s specs as a ballpark.

First I put a capo on the first fret and used my finger to press down at my last fret (22nd). Now check out the gap between the E-string and 7th fret. Here mine is with a .011″ feeler gauge. Fender’s spec is .010″ for this particular Strat.

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Feeler gauges come in sets like this. The idea is the gauge should fit between the string and fret without pushing the string up at all.  Note: My feeler gauges have seen better days.

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Ok, the gap looks good. Now I’m going to adjust the string height to near Fender specs.

It’s ok to adjust the saddle height down with strings in tune. It is not a good idea to adjust the saddle up with strings in tune. This will put stress on your saddles and strings. So I always detune the string until it’s pretty loose then adjust the saddle up.

I like to adjust my strings as low as possible without major buzzing. It’s an iterative process. Lower string, tune, pick it at every fret, bend it at every fret. Sound good? then lower it some more.

I adjusted my string saddle so that the bottom of my low E-string was about 3/64″ from the top of the fret. Fender’s specs are 4/64″. I don’t shred or have a light touch so super low action is not my goal. My other string heights were in the same ballpark.

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At the end my guitar was within Fender’s specs and playable again! Ok, it probably could use a bit of fret work to fine tune it. But it’s a big leap forward from where it was the day I foolishly bought it.

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6 Responses to Truss Rod Adjustment: Follow up

  1. AndrejG says:

    At the start I thought, you are forcing too much too fast, but after checking dates of previous repair, I saw, that you gave the neck quite some time to work it out by itself, before taking extreme measures. Nice reading.

  2. cporro says:

    thx. there was probably a week or two in between. but i don’t think much changed. i’m just happy to get it into fender specs.

  3. Henry says:

    Chris:

    I read both of your threads on this truss rod problem. You provided the most thorough discussion of this problem and how to repair it that I have found online. But, I still have a question. If the truss rod nut is already very hard to turn and there is still a bow in the neck should the truss rod nut be loosened before doing the clamping procedure you describe here. That is loosen the nut, apply the clamp and then tighten the nut, clamp some more, tighten some more, etc.

  4. cporro says:

    thx.

    i can’t see any harm in following the clamp with the truss rod nut as i did in my post. but i can imagine a problem if you have a dual adjustment truss rod and don’t follow the clamp with the nut. which do you have?

    this back bowing with a clamp just takes some strain off the truss rod so you don’t have to crank it hard (which you shouldn’t do). but some necks just have wood that’s not shaped right. so you can insert a washer, backbow and adjust, and the thing still isn’t right after a week or 2! for that i’m looking into using heat and clamps. there may be a truss rod adjustment part 4. needless to say all things would be better if i just stopped buying guitars with bad necks. 😀

  5. STEVE says:

    You say 3/64 in pic above but looking at the scale it is 3/32 fender does say 4/64 which in turn is 2/32 which is 1/8th inch. The pic looks like about 6/64

  6. cporro says:

    you’re right. it is 3/32. trust the picture!

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