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  #1  
Old 12-05-2021, 06:49 PM
funkymonk#9 funkymonk#9 is offline
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Default Bridge Placement for Optimal Saddle Question

Hello, it has been a while perusing this forum and it has yet to let me down.

It's just a get 15 opinions type of day.

I am drawing out my bridge placement and through all the hemming and hawing and line drawing, I found myself in a tight situation.

Definitely not the make a new bridge "too far" but certainly in the realm of optimal theory and kick it a bit in this way or that way.

This is for a 4 string Tiple (G,D,B,E)

So I have drawn out my braces on the top, in order to place the rear of bridge edges over them....just slightly.
On the bass side, there is about a 16th in front of the saddle area and about a 1/4 from the front of saddle (3/32- 1/8) to the ramp behnd.

3 issues
Placement of the bridge in regards to the braces.
Placement of the bridge in regards to the space between saddle and ramp.
And of course the saddle placement for best intonation.

1. Do you always put the compensation measurement to the exact front of the saddle?
2. If I move the bass side of saddle back, it may get too close to the ramp.
3. If I move the bridge back to allow more room, its wing will be somewhat on the inside edge of braces.

Right now this is just guessing as the compensation with action and string guage flexible.

Is there a sweet spot, allowable maneuver or not that big a deal



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  #2  
Old 12-06-2021, 03:48 AM
Talldad Talldad is offline
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One factor you have not discussed is the pull of the strings on the saddle. If there is not enough structure in front of the saddle then this can break the bridge forwards! More problems sorry.

I always put the compensation to the middle of the saddle, gives me a little wiggle room, I also use a Stewmac Intonator before I cut the slot..

There is a large school of thought that having an interconnected bracing system is a great thing. I can't quite see why the bridge must be exactly over the braces although I can understand the arguments that it should be very, very close.

There's three options for you, 12 more required.
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Old 12-06-2021, 05:05 AM
funkymonk#9 funkymonk#9 is offline
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Thanks, I should have mentioned the area in front of the saddle on the bridge.
It's not a problem now but if moved forward it could be.

So right now there is 3/16 in front of the treble side saddle area. Depending on how long the saddle goes past the strings, it could be less.
So the bridge could potentially be moved back a 1/16th at most as
Typically there is an 1/8th of material in front.

The plans show that the bass side of saddle is closer to the ramp but I thought having it so close and even partially exposed in the back might be a problem.

Thanks for the saddle perspective, it certainly makes sense.
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Old 12-06-2021, 07:11 AM
Fathand Fathand is offline
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Is your tiple steel or nylon strung? Nylon strung instruments tend to have straight non compensated saddles.

You can determine best position for intonation by adding a temporary tailpiece, leave your bridge floating, tune to pitch and slide bridge around until intonation is correct.
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Old 12-06-2021, 01:56 PM
Howard Klepper Howard Klepper is offline
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There is a lot in your posts that I do not follow. But from what I can understand, you appear to be taking the brace locations as a given, and then working on bridge placement.

That is the opposite of how a bridge and bracing system should be designed. Always locate the saddle first. Then design the bridge so the saddle is appropriately located in the bridge. Then design the braces to fall where you want them under the bridge.
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Old 12-06-2021, 02:47 PM
Alan Carruth Alan Carruth is offline
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Note that tipping the saddle back, so that it's angle bisects the break angle of the strings, will eliminate the tipping force that's trying to break out the front of the saddle slot. That's how they get those tall skinny bridges to stay up on fiddles.

There's no reason not to have the strings ride right off the front edge of the saddle, so long as you're sure you got that right! My teacher used to say he'd never seen a guitar get longer as it aged: you seldom have to move the saddle forward, but sometimes you have to move one back.
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Old 12-06-2021, 06:44 PM
funkymonk#9 funkymonk#9 is offline
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Quote:
Originally Posted by Fathand View Post
Is your tiple steel or nylon strung? Nylon strung instruments tend to have straight non compensated saddles.

You can determine best position for intonation by adding a temporary tailpiece, leave your bridge floating, tune to pitch and slide bridge around until intonation is correct.
It's a steel string 3 courses 4 sets.
Thats a really interesting idea, I will definitely consider that.

Quote:
Originally Posted by Howard Klepper View Post
There is a lot in your posts that I do not follow. But from what I can understand, you appear to be taking the brace locations as a given, and then working on bridge placement.

That is the opposite of how a bridge and bracing system should be designed. Always locate the saddle first. Then design the bridge so the saddle is appropriately located in the bridge. Then design the braces to fall where you want them under the bridge.
Sorry i tried to write it clearly, but I understand it can be misleading.
I built this Colombian Tiple from plans taken from the Guild of American Luthiery, so the system is predetermined. Although my scale length was a hair longer. I Used a magnet to locate the braces and transferred them on top. The bridge is wider than the plans and I've seen a lot of tiples with independent saddles for ideal compensation so I may be doing it in reverse as you say.

Quote:
Originally Posted by Alan Carruth View Post
Note that tipping the saddle back, so that it's angle bisects the break angle of the strings, will eliminate the tipping force that's trying to break out the front of the saddle slot. That's how they get those tall skinny bridges to stay up on fiddles.

There's no reason not to have the strings ride right off the front edge of the saddle, so long as you're sure you got that right! My teacher used to say he'd never seen a guitar get longer as it aged: you seldom have to move the saddle forward, but sometimes you have to move one back.
Thats a interesting idea, plus the angle will move my saddle top a little further back and thus the compensation point a little further towards the front.
So you angle the whole slot a few degrees?
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Old 12-07-2021, 08:22 AM
rmmottola rmmottola is offline
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The GAL (Alberto Paredes) tiple plan includes accurate saddle and nut details for saddle and nut compensation for the individual strings. If the scale length of your instrument is truly "a hair" longer than the plan, the compensation values for the plan will work out fine. Note that, as in that plan, compensation must be done on an individual string basis, not on a per-course basis. This requires some picky work with a narrow file. Also note that, if the scale length of your instrument is even a bit longer than in the plan, the most commonly available tiple string set will not work. The B octave strings are too small in diameter.
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Last edited by Kerbie; 01-24-2022 at 09:53 AM. Reason: Edited according to rules.
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Old 12-07-2021, 11:19 AM
Alan Carruth Alan Carruth is offline
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Yes, I angle the whole saddle slot back from vertical, as seen from the side. I've been using a 9 degree angle. It's not the bisector for any string (that varies) but it's pretty close, and is enough to be a big help. It's also about the right angle the more or less automatically adjust the compensation if you need to raise or lower the saddle height.

When I'm making the saddle for a 12-string I use a wide one (3/16" minimum), and set out the 'break' lines for both the regular and octave strings all the way across. The saddle top is rounded off behind the back line for the 'regular' strings, and filed away at a fairly steep angle in front of the line for the 'octave' strings. I then use a triangle file to make a V-groove between the two lines. The end of the saddle is 'M' shaped. When the strings are installed I use a small round file to notch out whichever point on either ridge is not supposed to be supporting that string. This is less fussy than snaking the ridge line back and forth for each string, and tends to look as though you meant it, which is always nice. Sadly, there's no such simple solution for nut compensation on 12s.
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Old 12-08-2021, 02:11 AM
funkymonk#9 funkymonk#9 is offline
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Quote:
Originally Posted by Alan Carruth View Post
Yes, I angle the whole saddle slot back from vertical, as seen from the side. I've been using a 9 degree angle. It's not the bisector for any string (that varies) but it's pretty close, and is enough to be a big help. It's also about the right angle the more or less automatically adjust the compensation if you need to raise or lower the saddle height.

When I'm making the saddle for a 12-string I use a wide one (3/16" minimum), and set out the 'break' lines for both the regular and octave strings all the way across. The saddle top is rounded off behind the back line for the 'regular' strings, and filed away at a fairly steep angle in front of the line for the 'octave' strings. I then use a triangle file to make a V-groove between the two lines. The end of the saddle is 'M' shaped. When the strings are installed I use a small round file to notch out whichever point on either ridge is not supposed to be supporting that string. This is less fussy than snaking the ridge line back and forth for each string, and tends to look as though you meant it, which is always nice. Sadly, there's no such simple solution for nut compensation on 12s.
That's very detailed thank you, love it. Yes I made a 12 string also and used a 3/16 nut which was very necessary. I don't have perfect pitch but have been playing long enough to be irritated by slightly off intonation.

So as far as the saddle position in the bass side, you see no problem with having it placed right in front of the ramp for the break angle behind or should there be some bridge material seperating it for stability?

Also is having the wings towards the back being over the braces a critical issue?
Thanks so much for your insight Alan.
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Old 12-08-2021, 11:55 AM
Alan Carruth Alan Carruth is offline
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"So as far as the saddle position in the bass side, you see no problem with having it placed right in front of the ramp for the break angle behind or should there be some bridge material separating it for stability?"

My main concern with that is getting the break angle right. The experiments I've done on this indicate that once you get 'enough' break angle (which is probably in the range of 12-18 degrees) more doesn't help the sound. What it does do it increase the tipping force on the saddle that deforms the slot and breaks out the front. Tipping the saddle back helps with that, as I've said.

Is it possible to plug and re-drill the string holes in the tie block to move them up a bit and reduce the break angle, if that's an issue? They can be drilled at an angle upward from the back, if that helps.

"Also is having the wings towards the back being over the braces a critical issue?"

I do feel it's helpful (at least) to have the top bracing run under the bridge. I'm not familiar with the brace layout on that particular plan, so I don't know why you're having problems with the bridge placement relative to them. Normally one designs the top, bridge, and bracing together. If you're copying the bridge from an existing plan that should have been done for you. If the bridge placement relative to the bracing is off then you may need to re-work the bridge design to make it all come out right. In most cases it's more of an issue than others, and without being familiar with the layout and the reasoning behind it I can't say.
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