What are the group's feelings about the ideal distance measured from the top of a guitar to the strings, right in front of the bridge. This would be on a Martin D-18.
I'm first with 14 mm :-)
The ideal distance would only hold if the neck set, nut notches, soundboard flatness, and truss rod adjustment are spot on.
Sure. it's a complicated story, but for the purposes of this question, assume all that has been done. What I'm asking about is the ideal in terms of a target measurement.
On a new[ish] guitar? On a Martin with a medium bridge height it's just about 1/2" at the D and G strings.
No, it's a '41. A guy overset the neck. The bridge was already thin, so it now has a very tall saddle but the action is way low for me. Sure, I could put a normal-thickness bridge on it and see what happens, but I would like to be able to include this measurement to help determine just how bad it really is. i.e., would the guitar need a "reverse" neck set to lessen its angle in the body in order to line up with a correct medium-height bridge, and what would be the ideal string height from the top? That, seems to me, would help determine how thick the bridge needs to be.
Yep, one half anch.
A half inch would be average, but it varies. As I look at it, the height of the bridge is one of the less important measurements and it can be modified to account for other factors in the setup. Apparently, at the Martin factory they make bridges of varying height (but otherwise identical dimensions). The neck angle can never be fitted with absolute precision and there is some variation from one guitar to the next. Likewise for the arch of the top. Once the neck is attached to a guitar they place a straight edge down the fingerboard and project it to the bridge location to determine whether this instrument should have a tall, medium or short bridge. They then pull the appropriate size bridge out of the drawer and glue it on. Obviously there are limits to how far you can push this variable - but the point is that it is a variable, not an absolute.
There is a good discussion of variation in Martin bridge height here: