Basic Question

Extend the centreline of the neck over the body, and that is the centre of the bridge. You'll usually want it at 90 degrees to that line.
 
I do it a bit different than these guys I guess. I lay a ruler along the edges of the fretboard, then measure from the nut along the imaginary line formed by the ruler extending down over the top, to the desired bridge placement (1/4" ahead of the scale length for my bridges). This gives me two points on the top effectively centered on the fretboard. The bridge gets placed with those points right on it's front edge, centered on them from side to side.
 
You follow the center line of your fretboard to give the distance and center using a 24 inch steel ruler (scale length + compensation) and then measure off the side of the fretboard on either side (I use the 10th fret) to get the bridge perpendicular to the nut. Tape the bridge down as you go to prevent it from moving or you will be chasing your tail because just as you get everything perfect you will sneeze and it will move by an RCH making you have to start all over again which leads to frustration and bad words. You have to get this part right Jerry.
 
I do it a bit different than these guys I guess. I lay a ruler along the edges of the fretboard, then measure from the nut along the imaginary line formed by the ruler extending down over the top, to the desired bridge placement (1/4" ahead of the scale length for my bridges). This gives me two points on the top effectively centered on the fretboard. The bridge gets placed with those points right on it's front edge, centered on them from side to side.

Similar here. I mark the position by damming the area with masking tape. I measure length first with the steel ruler clipped to fretboard providing just enough downforce so I can put a piece of masking tape across the front of the bridge. I then project the sides of the fretboard as above onto that piece of masking tape, centre, cross check against alignment of strings on bridge vs fretboard with steel ruler, cross check length. Tape on side positions check length. Check string alignment. Check height. Check length again. Check everything I haven't thought of. Check measurement of nut to 12th fret is just a tad less than the measurement from 12th fret to saddle position. Check allignment of strings. Check measurement of 12th fret to saddle position is just a tad more than the measurement from nut to the 12th fret. Put tape behind the bridge. Cross check the tape outlines the bridge placement. Check everything above again.
Glue and clamp the bridge in position.
When the glue dries, wonder why it is in the wrong position.
Try again, get it right the second time..
 
you will find one of these very useful for marking out bridges and checking neck alignment.
https://www.isomars.com/p/set-square-geometrical-nautical-art-sgnp/. Draw a centre line as others have suggested and mark out the length required. Align the set square in the desired position and draw a perpendicular line across. Then extend a rule along each edge of the fretboard to mark out the outer edges on the bridge line you've just drawn.
This is an idea I picked up from Pete Howlett, and has proved to be a very useful tool.
please note the size, it's large and not one of tiny little things we use to have in our school days.
 
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Thanks for all the ideas. I think I was over-thinking it - taking too many measurements. I hope to tape over the bridge area and get some color on it today, probably Minwax Natural.
 
Similar here. I mark the position by damming the area with masking tape. I measure length first with the steel ruler clipped to fretboard providing just enough downforce so I can put a piece of masking tape across the front of the bridge. I then project the sides of the fretboard as above onto that piece of masking tape, centre, cross check against alignment of strings on bridge vs fretboard with steel ruler, cross check length. Tape on side positions check length. Check string alignment. Check height. Check length again. Check everything I haven't thought of. Check measurement of nut to 12th fret is just a tad less than the measurement from 12th fret to saddle position. Check allignment of strings. Check measurement of 12th fret to saddle position is just a tad more than the measurement from nut to the 12th fret. Put tape behind the bridge. Cross check the tape outlines the bridge placement. Check everything above again.
Glue and clamp the bridge in position.
When the glue dries, wonder why it is in the wrong position.
Try again, get it right the second time..

How much is a tad? :D

Yes, I know what you mean about finding errors after things are glued in place. :)
 
Putting double sided tape on the bottom of the bridge while doing all the alignment and measurements helps keep it from moving by accident while fiddling around with it.
 
How much is a tad? :D

As much as you need for intonation :D

On a tenor I shoot for the saddle center line to be behind the scale length by .1". With a 1/8" saddle that gives you an intonation "compensation range" of from .0375" to .1625" behind the scale length.
 
As much as you need for intonation :D

On a tenor I shoot for the saddle center line to be behind the scale length by .1". With a 1/8" saddle that gives you an intonation "compensation range" of from .0375" to .1625" behind the scale length.

Okay, so a tad is imperial, rather than metric. Good to know. :)

When you say "behind," you mean the saddle is 1/8" farther from the 12th fret?
 
When you say "behind," you mean the saddle is 1/8" farther from the 12th fret?

Correct. The compensation distance is further from the nut. The distance depends on your scale length. I use 3/32 on a 17 inch scale tenor sized instrument. This is a "rule of thumb" measurement or a "tad" which means it is inexact. And then we get into the subject of compensation and intonation and all that which has been covered MANY times on this forum.
 
Correct. The compensation distance is further from the nut. The distance depends on your scale length. I use 3/32 on a 17 inch scale tenor sized instrument. This is a "rule of thumb" measurement or a "tad" which means it is inexact. And then we get into the subject of compensation and intonation and all that which has been covered MANY times on this forum.

This will be 17" scale. "Inexact" is my specialty. :D
 
Are you making your own bridge? If so, you can opt for a thicker saddle to give yourself more compensation range.

Or just stick with what ya got and put it "a tad" longer than 17" if you're not too concerned about intonation on the higher frets. :D Really, there is a degree of wiggle room in terms of scale length/intonation since you can adjust the witness point forward/backward across the thickness of the saddle depending on how you shape it. But the thing you definitely don't want to mess up is the side to side placement relative to the fretboard, there's not much margin for getting it wrong before the instrument becomes unplayable, and there's no real way to fix it if you get it wrong other than popping the bridge off and regluing it, which is a pain.
 
Are you making your own bridge? If so, you can opt for a thicker saddle to give yourself more compensation range.

Or just stick with what ya got and put it "a tad" longer than 17" if you're not too concerned about intonation on the higher frets. :D Really, there is a degree of wiggle room in terms of scale length/intonation since you can adjust the witness point forward/backward across the thickness of the saddle depending on how you shape it. But the thing you definitely don't want to mess up is the side to side placement relative to the fretboard, there's not much margin for getting it wrong before the instrument becomes unplayable, and there's no real way to fix it if you get it wrong other than popping the bridge off and regluing it, which is a pain.

Thanks. I'm using a store-bought bridge and saddle. I'll work on getting the bridge centered and then let it be a tad lower.
 
I think he (or she) means the saddle can be wider so that you can file the contact points either forward or backward to dial in intonation.
 
Just to make sure that everything is spelled out.
You are trying to figure out where to place the "bridge", but all the key measurements that you need to take into account are to the "saddle". Also note that the saddle "slot" in the bridge has a front face and a rear face.
Which slot face do you need to measure to? Great question.

If your saddle was thick enough, then what you could do is place the front face of the saddle slot right at the 17" mark and then have the total thickness of the saddle, finish at say the 17 4/16" or 17 5/16" mark and you would have enough room to make saddle adjustments with a file to get everything intoned correctly.

Since saddle material isn't that thick you don't have this luxury.
Often you see 3/16" quoted as the correct compensation needed for a 17" scale instrument however this is usually quoted to the MIDDLE of the saddle. Not the front or rear face.

Some/many builders use a special tool that holds a saddle for them and places it a measure distance from the nut for them.
Measuring by hand with a ruler is a little more complicated.

So, do we measure 3/16" compensation to the front face of the saddle slot? My experience is that this is too much compensation for the high strings and the intonation will be flat. Zero compensation to the front face of the slot and counting on the saddle thickness alone is too little compensation and the intonation will be sharp on a few strings.

My two bobs worth is that the front face of the nut slot can/should be compensated by 1/16", and if your using a 3/16" saddle thickness then you have a compensation range from 1/16" to 4/16" which should be enough.

The thinner your saddle material is, the more accurate you need to be.

EDIT again: Thinking further. Most saddle material is only 2/16" (about 3.2mm) isn't it, which means that you DO need to be more accurate. Using a saddle thinner than 2/16" may have benefits for some but your really making things hard for yourself.

Has anyone figure out the minimum and maximum compensation distances on a ukulele or are we all guessing?
Does someone have a better compensation figure for the front face of the nut slot than my 1/16" guess?
 
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Just to make sure that everything is spelled out.
You are trying to figure out where to place the "bridge", but all the key measurements that you need to take into account are to the "saddle".

Yes, I realize that, and I think I've narrowed it down. See my next post.
 
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