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View Full Version : Adjusting the action with a glued in through-saddle



SweetWaterBlue
07-29-2010, 06:36 PM
I recently traded a tenor for a Bobby Henshaw baritone born in about the same year I was (1950s). Its got a few nicks and scratches here and there, but I've got a few nicks and scratches myself after 60 years! It looks like this one, except mine has a new set of baritone strings.

http://www.box.net/shared/dlei21zvff

The good news is its in great shape mechanically with no cracks anywhere. The guy I traded it from was using it as a wall hanger, but I want to play it. Henshaw apparently followed Martin's lead and used what looks like a through-saddle glued in. The saddle is some sort of very hard wood, but its way too high for decent intonation. I've got over 3/16" of clearance on the biggest string at the 12th fret.

I have read an article on how to cut out the through saddles on some old Martins (http://www.frets.com/fretspages/Luthier/Technique/Guitar/Saddles/ThruSaddle/thrusaddle.html), but I dont want to go there if I don't have to. Since the saddle is wood and glued in, I would rather not have to use heat to get it out. Instead, I am thinking of just shaving a 16th" inch or so off the top with a sharp finger plane, keeping the same angle it has now. I also don't want to destroy any historical value. Here is a picture of mine:

http://www.box.net/shared/l8qnis9xix

Thoughts and/or suggestions?

Later edit - I just got a message from another UU member that has a Henshaw baritone. She said it had the same problem as mine, but she sanded the saddle down from the top (no way to get it out without heat etc). Her intonation is now good to the 12th fret. Sounds like it may be the way to go. Thanks Fran.

olgoat52
07-29-2010, 08:13 PM
I'm pretty new here so maybe take this with a grain of salt, but two things I can think of.

The trick with heat is to protect the areas you don't want to get hot. In your case, a piece of flat sheet metal like the use in duct work would do it. You would need to cut a slot in the sheet metal wide and long enough for the saddle to fit through without exposing the bridge. You probably want about 4 to 6 inches around the saddle covered by the sheet metal. Then you put some cardboard under the sheet metal and slip it all over the bridge. Use a heat lamp about 4 to 6 inches above the the saddle to heat it up. Or use an iron in direct contact with the saddle. On a guitar I would be feeling under the top for anything getting warm. Periodically try and gently lift the saddle out of the bridge. Eventually it will give. Clean up the glue in the bridge while it is still warm.

If you really want to plane, then get a large piece of cardboard and cut out the center in the same shape as the bridge then slip it over the bridge to protect the top. I would use a block plane instead of a finger plane. Use a pencil to mark the arc you want to trim down to on the saddle and plan down to the mark. If the finger board is flat, then you can plane a straight line. other wise trace the arc of the finger board onto the saddle. Go slow and do it in multiple attempts. If you go too low you will have to pull the saddle anyways. Better to plane it, string it, play it and plane again if needed.

Third option. Take it to a luthier and let a pro do the job. If it is a vintage piece it will be worth the cost Luthiers deal with this stuff all the time.

I recently traded a tenor for a Bobby Henshaw baritone born in about the same year I was (1950s). Its got a few nicks and scratches here and there, but I've got a few nicks and scratches myself after 60 years! It looks like this one, except mine has a new set of baritone strings.

http://www.box.net/shared/dlei21zvff

The good news is its in great shape mechanically with no cracks anywhere. The guy I traded it from was using it as a wall hanger, but I want to play it. Henshaw apparently followed Martin's lead and used what looks like a through-saddle glued in. The saddle is some sort of very hard wood, but its way too high for decent intonation. I've got over 3/16" of clearance on the biggest string at the 12th fret.

I have read an article on how to cut out the through saddles on some old Martins (http://www.frets.com/fretspages/Luthier/Technique/Guitar/Saddles/ThruSaddle/thrusaddle.html), but I dont want to go there if I don't have to. Since the saddle is wood and glued in, I would rather not have to use heat to get it out. Instead, I am thinking of just shaving a 16th" inch or so off the top with a sharp finger plane, keeping the same angle it has now. I also don't want to destroy any historical value. Here is a picture of mine:

http://www.box.net/shared/l8qnis9xix

Thoughts and/or suggestions?

Later edit - I just got a message from another UU member that has a Henshaw baritone. She said it had the same problem as mine, but she sanded the saddle down from the top (no way to get it out without heat etc). Her intonation is now good to the 12th fret. Sounds like it may be the way to go. Thanks Fran.

Philstix
07-29-2010, 09:32 PM
Since you want to play it, now would be a good time to check some other things affecting playability. Is the neck straight and the fretwork even? One high fret could cause you problems. How high is the action at the first fret? How is the nut? Before you mess with the saddle I would make sure these things are alright. Personally I would use a file to take the saddle down and as said above, slowly.

erich@muttcrew.net
07-29-2010, 11:34 PM
Looking at the picture I think the saddle does look very high, but I would still start with maths and measurements:

A = height of the nut (measured from the top of the fretboard to the bottom tangent of the string resting in its slot under tension)
B = height/thickness of the fretboard above the soundboard
C = height of the frets (measured from the top of the fretboard to the crown of the fret)
D = desired action above the 12th fret
E = height of the saddle above the soundboard


EDIT: I had a little quick helper calculation posted here but I fear it may have contained an error and have therefore removed it. If anyone is interested in the mathematics of figuring out how high the saddle needs to be, please let me know and I'll sit down and do the geometry.

SweetWaterBlue
07-30-2010, 02:26 AM
Since you want to play it, now would be a good time to check some other things affecting playability. Is the neck straight and the fretwork even? One high fret could cause you problems. How high is the action at the first fret? How is the nut? Before you mess with the saddle I would make sure these things are alright. Personally I would use a file to take the saddle down and as said above, slowly.

I checked the flatness of the neck and the action at the nut end, when I first started fiddling with it. The nut seems ok, with the business card test, where it will trap a business card at the first fret if you finger the 3rd fret and release it when you don't. I measure the unfretted distance to the largest string tangent at just about 1/32" at the first fret, so the nut seems ok to me.

The neck is showing a small amount of relief (bowing). I measure around 1/32" between the bottom of the straightedge and the middle frets when a straightedge is laid on the frets from first to last. I probably cannot do much about that, since there is no truss rod. Sanding the frets with a long sanding block would fix some of it, but may have other unintended consequences. The neck angle seems ok from just a straightedge test, but the slight bow makes it difficult to judge exactly.

I think your suggestion of using a file on the top of the nut sounds better to me than a plane or sand paper. Thanks for the suggestions.

SweetWaterBlue
07-30-2010, 02:31 AM
Thanks eric. I will make some more measurements today when the light gets better. I read your calculation before you took it away, but did not study it or commit it to memory [g]. I will have to take the relief of the neck into account in such calculations, or I will surely get buzzing on the frets closest to the body. I think the method of filing a little and playing, then repeating if necessary may be the easiest. I will probably do that, even if I do calculations and scribe a line where it "should" be. There is no crown on the fretboard from side to side, so at least the saddle can be filed straight across.

mm stan
07-30-2010, 05:18 AM
Aloha SweetWaterBlue,
Sounds like a good plan, filing or sanding a little at a time and playing.....since there's no reverse if you over do it...except repacing the saddle...
Gee, sounds kinda extreme sanding the frets though, don't you think??I've heard someone clamp a straight edge down a fretboard to level the frets evenly..
don't know how that works...but a few clamps though..

thistle3585
07-30-2010, 05:53 AM
I put a bit of relief into my necks. One way to reduce the amount of relief in a non-truss rod neckis by replacing the frets with ones that have wider tangs. For example, if you go from a tang with .023 to one with .025 width then you have a difference of .002. Multiply that by the number of frets you have and you will get an idea of the amount of relief it will take out.

erich@muttcrew.net
07-30-2010, 12:25 PM
Thanks eric. I will make some more measurements today when the light gets better. I read your calculation before you took it away, but did not study it or commit it to memory [g]. I will have to take the relief of the neck into account in such calculations, or I will surely get buzzing on the frets closest to the body. I think the method of filing a little and playing, then repeating if necessary may be the easiest. I will probably do that, even if I do calculations and scribe a line where it "should" be. There is no crown on the fretboard from side to side, so at least the saddle can be filed straight across.

OK, I did the math again and am pretty sure I have it right this time:

A = saddle height (above the soundboard)
B = fretboard height (above the soundboard)
C = nut height (above the fretboard up to where the strings rest in their slots)
D = fret crown height (above the fretboard)
E = nut clearance (= nut height C - fret height D)
F = desired clearance above the 12th fret

Now we can calculate a ballpark figure for the saddle height:


A = B + D + 2 * (F - E)
saddle height = fretboard height plus fret crown height plus twice the difference between the 12th clearance and the nut clearance

This is assuming the neck/fretboard is straight with the body and does not take any portential relief/bowing of the neck into account.

Please also keep in mind that this is just an approximation. It won't tell you whether you need to lower the saddle or exactly how much you need to take off, but it should give you an idea of whether the saddle is way too high, or maybe just a little too high, or even just about right (which would mean you probably need to look at other issues).

Hope this helps - YMMV

70sSanO
08-05-2010, 11:11 AM
An old rule of thumb for guitar was the saddle is twice the 12th fret. Reducing the string height at the 12th fret by 1/16 inch means a 1/8 inch reduction at the saddle.

Because you are removing so much material, you need to know where the intonation is before you start. If it intonates fine but the string height is just too high, then as you lower the string height, the intonation point needs to move forward. It is just a matter of where the strings cross the saddle now and if there is enough saddle material in front of that point. If it intonates sharp, due to the high action and more string stretch when pressing down, you will want to keep the intonation point closer to where it is now.

I have not bought into the paper-clip approach as the exact point for intonation when also adjusting height. I just take my time and check it often.

John