#1
Hello,

I'm no n00b to guitar repair but I'm no expert, either. I know how to adjust action but my question is what is the CAUSE of poor action?

I have two guitars whose action can't go very low without having dead frets, I'm thinking that replacing the bridges would alleviate their poor action.

Am I correct or is it a combination of things that causes poor action?

Thanks in advance!
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#2
Neck angle, fret level-ness (if that's a word), bridge height, etc. There are several causes for bad action.

If it's a bolt on neck, you may want to try shimming the neck before you do something like replacing it.
#3
well it may not necessarily be the bridge. It could be the neck. If you take all of your strings off at the same time when you change them ( I have a friend who used to do that ) then it can warp your neck. Or if you change between tunings a lot. And I mean like from drop A# to standard, not drop D to standard or anything small like that. Various things can happen to warp your neck. But if it is just the bridge then you may be able to replace it to help, but generally since you can lower the action with the bridge, a new bridge probably wouldn't do much. You would put the new bridge in and lower the action with it and still end up with dead frets. Hope this helped.
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#4
well, first of all, how good are the guitars you own?
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#5
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Hello,

I'm no n00b to guitar repair but I'm no expert, either. I know how to adjust action but my question is what is the CAUSE of poor action?
You're being just a tad sloppy with the terminology.

First: Action isn't good or poor. It's either high or low. The more greater the distance the string needs to be deflected to make contact with the strings, the higher the action. Since most people prefer low action, you could say high action is poor. But really, you shouldn't.

Second: The "cause" of high action is the height of the nut and bridge in relationship to the frets. It's that simple. To lower the action, cut the nut slots deeper and/or lower the bridge.

Quote by ndfcartman
I have two guitars whose action can't go very low without having dead frets, I'm thinking that replacing the bridges would alleviate their poor action.

Am I correct or is it a combination of things that causes poor action?
Now we get to what you REALLY want to know. What limits the lowest setting of action before you have problems.

If your bridge can go low enough to cause problems, the replacing the bridge won't help a bit. It's job is to set the height of the end of the string. It is functioning properly.

The nut isn't easily adjustable, but it's height is very important. the bottom of the nut slots should fall in line with a line drawn across the tops of the frets. Usually the nut slots aren't quite that deep. This is still acceptable. But if the nut is excessively tall, you will also need to have the bridge set high as well. Even with a perfect fretboard, a nut that is too high will limit how low you can set the bridge.

If you were to draw a line from the top of your first fret to the top of the last, all the frets in between should almost contact that line. There should be only a slight bow, such that the frets near the half distant point between the first and last frets have a gap of about 0.005 inches from that imaginary line. That's about half the thickness of your high e string.

If there is any "waviness" in the height of your frets, this will limit how low you can set the action without having problems like "dead frets".

Fret leveling and having the trussrod adjusted to allow the string tension to bow the neck only slightly will be very important in achieving low action without problems.

The bridge height can be adjusted. Unless the saddles are fixed height and the radius differs too much from the radius of the fretboard, the bridge is likely not a limiting factor.

I hope that helps.
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