Stupid question alert: Trem installation/Scale length

Haych

So for my parts-caster build I will need to install my trem, which in my case will be a Schaller vintage tremolo.

I've scoured Google for schematics but haven't found anything useful yet.

The guitar will be 25.5" in scale, but from the nut to where?  Since the saddles are movable for intonation purposes what does 25.5" mean?  I know the technical definition is 12.75" from the nut face to the crown of the 12th fret X 2 but since the end point is variable to about 3/8" or so, where do I draw the line, so to speak?

Is the midway point between the extremity of the saddle's fore and aft movement a safe bet or am I misunderstanding the concept?

The end point for the scale length will determine where I drill the holes for the bridge posts so I want to make sure I get this right, or am I obsessing over something that isn't so critical???

TIA

olafgarten

You want to work out roughly where the saddles will be when intonated and base it off of that.

Keep in mind that the Nut to Bridge measurement is double the scale length.

Haych

olafgarten said:

You want to work out roughly where the saddles will be when intonated and base it off of that.

Keep in mind that the Nut to Bridge measurement is double the scale length.

Thanks, but on which string, since there can be quite a variation between them all?

ICBM

Set the top E saddle as far forward as it will sensibly go - which on that bridge is with the intonation screw end flush with the inside of the slot in the saddle - and put that point exactly 12.75" from the crown of the 12th fret on the side nearest the bridge. No string will ever intonate further forward than this. If you want to be extra cautious, move it towards the neck by a millimetre or so - but make sure you then don't run out of room to intonate the low E as far back as you need to.

Haych

ICBM said:

Set the top E saddle as far forward as it will sensibly go - which on that bridge is with the intonation screw end flush with the inside of the slot in the saddle - and put that point exactly 12.75" from the crown of the 12th fret on the side nearest the bridge. No string will ever intonate further forward than this. If you want to be extra cautious, move it towards the neck by a millimetre or so - but make sure you then don't run out of room to intonate the low E as far back as you need to.

Thank you, much appreciated, I'll use your advice, and actually now you've said what you have I can fully see the logic in it so it's almost a "D'oh!" moment, but I'm still glad I asked.

olafgarten

Haych said:

olafgarten said:

You want to work out roughly where the saddles will be when intonated and base it off of that.

Keep in mind that the Nut to Bridge measurement is double the scale length.

Thanks, but on which string, since there can be quite a variation between them all?

I meant roughly in the middle of all of the saddles.

It's not really that critical unlike with an acoustic because the saddles have quite a lot of adjustment.

ICBM

olafgarten said:

I meant roughly in the middle of all of the saddles.

It's not really that critical unlike with an acoustic because the saddles have quite a lot of adjustment.

I would say it's quite critical. All strings intonate correctly *longer* than the scale length, never shorter. If you put it with the scale length in the middle of the adjustment range you're wasting half of it, and you can easily run out of length for the low strings to go back far enough - the total adjustment range is only about 3/8", and that's not much more than the usual difference between the two E strings, so it is important to get it right.

Sporky

ICBM said:

Set the top E saddle as far forward as it will sensibly go - which on that bridge is with the intonation screw end flush with the inside of the slot in the saddle - and put that point exactly 12.75" from the crown of the 12th fret on the side nearest the bridge. No string will ever intonate further forward than this.

This is by far the most sensible explanation I've ever read  

ICBM

Sporky said:

This is by far the most sensible explanation I've ever read  

I will confess that this knowledge was gained by fitting Floyd Roses to several - what were then not perceived as - vintage guitars in the 1980s :-O ... if you're working on someone's favourite old guitar you really have to get it right first go.

WezV

just to add to @ICBM's advice.   Theoretically you do never need to move the saddle shorter than the scale length, but there are 2 very good reasons to set saddles slightly back for the initial positioning.

1) spring tension.   The saddles on fender style bridges will rattle less the further back they are set. I prefer to set fender styles bridges (or anything with springs behind the saddle) with the saddles 3/4 of the way forward, not all the way forward.   This still allows more than enough adjustment for intonation, but keeps nice tension on the spring.   Obviously you can just change the springs if needed.

2) Fudge room.   we all need it sometimes.   there is no shame in it.  Call it a safety net if you prefer.  Use potential wood movement to justify it if you think you are perfect.