Floating Bridge/Straight Edge Measurement

[Bill Eisele]

Hi All,

I have been trying to find the procedure for checking neck angle with respect to an archtop floating bridge by placing a straight edge on top of the frets and seeing where it meets up with the floating bridge and saddle. I have been able to find the procedure online for flat top guitars but not for floating bridge archtop guitars. And, I am sure someone has posted it on the forum but my searches haven't turned up anything. Please let me know how this is done and what a correct result looks like. Thanks!

Bill

[sgosnell]

I don't know how that's done, because it's not usual to bother with measuring, because the bridge is usually adjustable. One place to look is Ken Parker's Archtoppery series on YouTube. He uses a non-adjustable bridge, but a totally different method of attaching the neck, and adjusts action by raising or lowering the entire neck. I don't recall how he measures the needed height of the bridge, but it could be as high or low as wanted, just by adjusting the neck height. If you haven't seen his instruments, you should take some time to watch his series, although it's perhaps too long and detailed for some. If neither the neck nor the bridge will be adjustable, then the method used for flat-tops should work.

[Freeman Keller]

My rule of thumb for any guitar is to set the neck so the fret plane just touches the tops of the saddles at the very lowest adjustment. That almost always results in acceptable action and adequate adjustment range.

[garybaldy]

My rule of thumb for any guitar is to set the neck so the fret plane just touches the tops of the saddles at the very lowest adjustment. That almost always results in acceptable action and adequate adjustment range.

Do you 'choose' the minimum bridge height based on the gap that that will be created between the guitar top and the tailpiece?

[Bill Eisele]

My rule of thumb for any guitar is to set the neck so the fret plane just touches the tops of the saddles at the very lowest adjustment. That almost always results in acceptable action and adequate adjustment range.

Thanks for that information, Freeman! I just now made that measurement and the bottom of the straight edge sitting on the top of the frets is about 1/16" below the top of the saddle at its very lowest adjustment. I'm assuming that's okay?

[Bill Eisele]

Do you 'choose' the minimum bridge height based on the gap that that will be created between the guitar top and the tailpiece?

Are you referring to the need to obtain an appropriate break angle over the saddle based on the distance between the bottom of the strings and the guitar top as they come out of the tailpiece towards the bridge?

[garybaldy]

Are you referring to the need to obtain an appropriate break angle over the saddle based on the distance between the bottom of the strings and the guitar top as they come out of the tailpiece towards the bridge?

Sort of! It's just that with the lowest height of the bridge and the upward bow of the guitar top under the tailpiece, the underside of the tailpiece could touch (or even press down on) the guitar top. I've seen problems of that kind.

[Freeman Keller]

Thanks for that information, Freeman! I just now made that measurement and the bottom of the straight edge sitting on the top of the frets is about 1/16" below the top of the saddle at its very lowest adjustment. I'm assuming that's okay?

I come from a flat topped acoustic guitar background where you want the fret plane to hit the top of the bridge. With a reasonable saddle height of about 1/8 inch above the bridge you will have nice action on the neck. I like between 60 and 90 thousands at the 12th fret. With the adjustable archtop bridge all the way down the strings would be just laying on the fretboard - adjusting up by about 1/8 again gives acceptable action and keeps you in the range of adjustment. This works for most electric bridges too, but kind of falls apart with classicals. There are a couple more assumptions here - minimum relief and low nut action - I just assume that the f/b is flat when I'm setting the neck.

Are you referring to the need to obtain an appropriate break angle over the saddle based on the distance between the bottom of the strings and the guitar top as they come out of the tailpiece towards the bridge?

Break over angle is something else and depends on the arching of the top, style of tailpiece and the way it is mounted. Neck angle factors in to that but my primary goal with neck angle is to get good playable action on the fretboard, then do whatever I need to get the break over.