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Bridge Location Math Check...


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I am laying out my templates for routing the neck pocket, and it occurred to me that if I make the jig long enough, I could create a notch in the back of the jig for helping appropriately locate the bridge.

The stewmac fret calculator suggests that you mount the gotoh hardtail bridge I purchased at 25.25 inches... That is, with the center of the forward most mounting screws 25.25 inches from the fretboard end of the nut. When I do this it appears that I would have to move the low E saddle almost all the way forward to make the distance from nut to saddle 25.5 inches... I'm thinking the better way is to move the saddle to the center most position and then measure such that that point is 25.5 inches from the nut, or am I missing something? Input is appreciated. Thanks.

At the moment I have misplaced my Melvyn hiscock book, but I'd still be double checking with this forum either way. Lol

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The method I use is to have the neck and neck pocket done before I mark out the location of the bridge. That way I can tweak the bridge location relative to the position of the neck, rather than try and work the other way around. I'll have the neck built to a point that it can be fitted into the neck pocket and the fretboard slotted, and temporarily install the neck on the body with clamps. With hardtail bridges I wind the high-E saddle all the way out as far as it will go without it popping off the end of the screw, and then back it in a bit. I'll then take a steel rule and measure from the high-E nut line to the breakpoint of the high-E saddle - that's your scale length. You will probably find that in order to intonate the high-E properly once the guitar is finished the saddle will need to be wound back further still.

Don't use the low-E saddle to measure your scale length. The thicker wound strings invariably need to have a longer scale length in order to intonate properly, and will always have their saddles wound back further away from the nut.

As long as you position your bridge with the high-E saddle breakpoint located at your scale length, and also perpendicular to your centreline, the exact (measured) location of the mounting screws becomes irrelevant. Just drill them where the bridge sits, making sure it's all square and centred.

RAD does some good photo-essays regarding hardtail bridge installation. Browse some of his S9 build threads and you should be able to see how it's done.

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Unless it requires very specific placement I don't mark out the bridge location until the neck is in place or can be located properly. For example, in my recent bass build I marked a rough location of the "scale end" as worked out as a quarter of the scale length from the mark on the body where the 24th fret would lay. This was satisfactory enough until the bridge came to be fitted in which case I dropped all of the saddles as far forward as they could go in their intonation range and measured that up against the bridge post locations, drew these up and fitted the bridge, etc. I'm best off writing this up in a tutorial anyway, which is my intention. Sorry that this doesn't really describe anything useful....hangover, etc....RAD's threads are certainly an excellent place to start reading on bridge placement.

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yeah - measure with the actual bridge in place - but remember that saddles should only ever need to be moved back from the nut to intonate properly - so it doesnt make sense to locate the bridge with the saddles set at their centre point as you just loose half the possible adjustment.

i set the saddles at least 3/4's of the way forward when measuring for the bridge location - that gives me most of the backwards travel as intonation adjustment and a bit of forward travel as fudge room

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Thanks for the info. Exactly what I was looking for. I must admit to some additional ignorance... RAD ? S9 thread? I don't think I've stumbled across those on this forum yet. Are they here or on a different forum?

Ok, never mind... RestorationAD and his S9 guitar... The RAD threw me lol. Thanks for the heads up.

Edited by hittitewarrior
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Have you ever needed that fudge room Wez? My strategy has always been to set all the way forward and use that as the baseline, compensating slightly on the bass side a few mm if the bridge is especially "intonation-resistant" (ABR-1, etc).

i dont think i have ever actually needed it, never had a guitar not intonate. but in rebuild/repair terms i am happy to have a bit of fudge room existing at the bridge end

but there is another factor to consider especially with fender style saddles. putting the saddles 3/4 of the way forward gives more tension on the spring them having the saddle all the way forward. this helps keep them more solid and prevent unwanted vibration at the bridge and i am sure we could argue for a better tonal transfer too

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Have you ever needed that fudge room Wez? My strategy has always been to set all the way forward and use that as the baseline, compensating slightly on the bass side a few mm if the bridge is especially "intonation-resistant" (ABR-1, etc).

i dont think i have ever actually needed it, never had a guitar not intonate. but in rebuild/repair terms i am happy to have a bit of fudge room existing at the bridge end

but there is another factor to consider especially with fender style saddles. putting the saddles 3/4 of the way forward gives more tension on the spring them having the saddle all the way forward. this helps keep them more solid and prevent unwanted vibration at the bridge and i am sure we could argue for a better tonal transfer too

Those Fender bridges need all the help they can get :-D

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