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  #16  
Old 12-08-2020, 08:52 AM
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Victory Pete Victory Pete is offline
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Originally Posted by redir View Post
A straight edge on the frets hovering over the bridge should barely touch the top of the bridge. .1 inch is way too high as has been mentioned. That would be considered over set. It might still work but it might cause problems too. In that second pic is looks to me like the bridge is not glued down. is the neck glued in yet? If so I would make another taller bridge for it. If not then reset the neck angle down a bit.
My measurement is .05". The bridge is not glued down and the neck is.
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  #17  
Old 12-08-2020, 08:54 AM
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This is a 2016 Gibson 1938 SJ-200, it has significant clearance above the bridge also. Measurement from soundboard to strings is also 1/2". The action is great on this beast.







Last edited by Victory Pete; 12-08-2020 at 09:05 AM.
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  #18  
Old 12-08-2020, 09:19 AM
redir redir is offline
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Originally Posted by Victory Pete View Post
My measurement is .05". The bridge is not glued down and the neck is.
Ah ok it looks high in the pic. Depending on the guitar with my designs I typically go no higher then 1/32nd which is about .03".
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  #19  
Old 12-08-2020, 09:25 AM
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As a thought, do not forget to factor in the top rise as string tension pulls the top up. This should not be much, but still the difference needs to be accounted for when laying out a neck.
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  #20  
Old 12-08-2020, 09:29 AM
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Originally Posted by hat View Post
As a thought, do not forget to factor in the top rise as string tension pulls the top up. This should not be much, but still the difference needs to be accounted for when laying out a neck.
Right, thanks for the tip. This will lessen the gap I currently have
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  #21  
Old 12-17-2020, 09:04 AM
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Well it seems .050" was not enough clearance above the bridge for the neck set. The straightedge now sits right on top of the bridge. The top has risen and I guess the neck also has shifted because I had to lower the frets on the fretboard extension. I have my 1/2" string to top clearance but the action above the 12th fret is .125", which is too high.


Last edited by Victory Pete; 12-17-2020 at 11:25 AM.
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  #22  
Old 12-17-2020, 11:23 AM
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Here is another guitar with the .05" clearance above bridge during neck set. It has a slight gap above the bridge now. It is pretty good with .080 clearance at 12th fret. I have a bit more than the 1/2" clearance to top though. I could lower it a bit. So you get different results with different guitars obviously. It seems this one could have had less angle and the other could have had more.


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  #23  
Old 12-17-2020, 02:32 PM
M Hayden M Hayden is offline
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The key point is not an arbitrary 1/2”-above-the-soundboard for neck set.

Instead, it’s the relationship between the plane of the fingerboard and the front edge of the bridge. Even for Martin, bridges come in different heights, and they set for the height of the front of the bridge, not an arbitrary 1/2” measurement.

The 1/2” measurement is between the strings and the soundboard, and is considered an ideal to shoot for when the instrument meets the following criteria:
  • The plane of the fingerboard intersects the top of the bridge
  • There is a saddle installed in the bridge
  • The instrument is strung up and the strings pass over the saddle.

That’s when you’d ideally see about a half inch under the strings - but it can vary a bit either way, as long as the overall geometry is right.

OP is conflating an ideal setting for the full bridge-and-saddle height of the strings above the top with the neck set - the two are not the same.

As other wiser builders have noted, an overset neck (where the plane of the fingerboard overshoots the front of the bridge) is a recipe for putting too much stress on the saddle and risks breaking out the front of the bridge. Fixing it requires either resetting the neck to the plane-of-fingerboard-intersects-bridge-top geometry or a very, very thick bridge.

Last edited by M Hayden; 12-17-2020 at 02:37 PM.
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  #24  
Old 12-17-2020, 03:01 PM
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Quote:
Originally Posted by M Hayden View Post
The key point is not an arbitrary 1/2”-above-the-soundboard for neck set.

Instead, it’s the relationship between the plane of the fingerboard and the front edge of the bridge. Even for Martin, bridges come in different heights, and they set for the height of the front of the bridge, not an arbitrary 1/2” measurement.

The 1/2” measurement is between the strings and the soundboard, and is considered an ideal to shoot for when the instrument meets the following criteria:
  • The plane of the fingerboard intersects the top of the bridge
  • There is a saddle installed in the bridge
  • The instrument is strung up and the strings pass over the saddle.

That’s when you’d ideally see about a half inch under the strings - but it can vary a bit either way, as long as the overall geometry is right.

OP is conflating an ideal setting for the full bridge-and-saddle height of the strings above the top with the neck set - the two are not the same.

As other wiser builders have noted, an overset neck (where the plane of the fingerboard overshoots the front of the bridge) is a recipe for putting too much stress on the saddle and risks breaking out the front of the bridge. Fixing it requires either resetting the neck to the plane-of-fingerboard-intersects-bridge-top geometry or a very, very thick bridge.
So it seems the higher the bridge is the better it is for a saddle that doesn't stick out too much. I have 4 Gibson acoustics and my HD-28, none of them have the fingerboard plane sitting on the bridge, all of them have a space, all have the 1/2" measurement.
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Old 12-17-2020, 05:37 PM
Talldad Talldad is offline
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I think Charles explained it best. The 1/2Ē you enjoy is considered to be a good compromise between power and stability. You could make it higher, the torque would increase, the volume would increase but it would be more prone to deformation. Volume doesnít equate to tone though.

The height of the bridge is not relevant to tone but to itís stability. A heavy bridge will dampen the sound so a lighter one is best. However if it is too flimsy it may break at the saddle. Again much work has gone in to bridge design and the ones you see are a compromise between weight and structural integrity especially around the front of the saddle.

There arenít really perfect measurements in a set up, more guiding principles and targets to get the tone that makes you want to play.
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  #26  
Old 12-17-2020, 05:50 PM
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Quote:
Originally Posted by Talldad View Post
I think Charles explained it best. The 1/2Ē you enjoy is considered to be a good compromise between power and stability. You could make it higher, the torque would increase, the volume would increase but it would be more prone to deformation. Volume doesnít equate to tone though.

The height of the bridge is not relevant to tone but to itís stability. A heavy bridge will dampen the sound so a lighter one is best. However if it is too flimsy it may break at the saddle. Again much work has gone in to bridge design and the ones you see are a compromise between weight and structural integrity especially around the front of the saddle.

There arenít really perfect measurements in a set up, more guiding principles and targets to get the tone that makes you want to play.
Thanks for the information, I realize there are a lot of variables. So apparently if people are setting the fretboard plane to sit right on the bridge, they must be using tall bridges.
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  #27  
Old 12-20-2020, 06:49 PM
M Hayden M Hayden is offline
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Quote:
Originally Posted by Victory Pete View Post
Thanks for the information, I realize there are a lot of variables. So apparently if people are setting the fretboard plane to sit right on the bridge, they must be using tall bridges.
Martin makes(AIR) three bridge heights to deal with this

Necksets are variable, and some are higher and some lower.

The different bridge heights simplify mass production by essentially increasing neck set angle tolerance - every neck doesn’t have to be x angle, every time; they can + or x- a bit, and do ok.
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  #28  
Old 12-21-2020, 02:21 AM
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Quote:
Originally Posted by M Hayden View Post
Martin makes(AIR) three bridge heights to deal with this

Necksets are variable, and some are higher and some lower.

The different bridge heights simplify mass production by essentially increasing neck set angle tolerance - every neck doesnít have to be x angle, every time; they can + or x- a bit, and do ok.
Right, I had a D-42 with a thick bridge resulting in a very low saddle with a low break angle. It did have the magic 1/2" clearance from soundboard to strings though.
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  #29  
Old 12-21-2020, 05:16 PM
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ArchtopLover ArchtopLover is offline
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Quote:
Originally Posted by redir View Post
A straight edge on the frets hovering over the bridge should barely touch the top of the bridge. .1 inch is way too high as has been mentioned. That would be considered over set. It might still work but it might cause problems too. In that second pic is looks to me like the bridge is not glued down. is the neck glued in yet? If so I would make another taller bridge for it. If not then reset the neck angle down a bit.
Excellent post, this is exactly how I understand neck angle geometry for a flattop.

However, for archtops (which I prefer), neck-set geometry is not as critical a concern for the structural integrity of the instrument. Although, where tone and volume is concerned, the neck-set geometries importance comes into play when the builder is determining the string break angle at the bridge. This break angle parameter has enormous ramifications in the overall tone and volume of the instrument, and the builder can actually "voice" the guitar by simply raising or lowering the string break angle for a particular sound to be achieved. Of note, James L. D'Acquisto made his ebony tailpieces adjustable, so that the customer could play his instrument and have the tailpiece adjusted for optimal tonal preference. What is most interesting, in this regard, is that the tonal differences are well understood; a low break angle gives a warmer more plush tone with less volume, conversely a higher break angle increases volume, and brightens the overall tonal character, but adds some harshness and acoustic artifacts, that many archtop players find annoying or disagreeable, so, finding that perfect Goldilocks sweet spot is really tricky .
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  #30  
Old 01-23-2021, 04:37 PM
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Both of these guitars have been lacquered and have gotten new strings. There is quite a bit of difference between them. They both had .050" clearance above bridge but have very different string clearances now. One is perfect and the other is pretty high. When I did these neck sets I did notice one was not at as much of an angle as the other. It was the one with the top that had no radius in it. I don't know why that had happened, both tops got glued the same way. I remember at the time that the tops, before braces, would sometimes warp if I left them on the bench overnight, I would then flip them over and they would straighten. I now hang them so they get equal air flow on each side. I guess if the top has no radius it will pull up more with string tension and that is how I got the high action. I did have the magic 1/2" string clearance to the top so I got some wiggle room to lower the saddle.
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