Questions: B-String Compensation

by John Calkin

Originally published in American Lutherie #100, 2009

Tom from Ohio asks:

I built a parlor guitar for a buddy of mine and it really turned out nice... except. The B string is really sharp. This is a 12-fret guitar with a 24.9" scale length. I added 2.5MM compensation and the action is very low. I further compensated the B string as far as it would go by lengthening its point on the saddle. I’ve really never had this problem before. Is it because of the 12-fret configuration? What’s the fix?

John Calkin from Greenville, Virginia replies:

Cut a bit of saddle material (bone, or whatever you used) and glue it to the back of the current saddle, but only behind the B string. Let the new piece rest right on the bridge so the saddle won’t be torqued, but don’t glue it to the bridge. Level the new piece with the real saddle, then use a piece of .010" wire under the B string to find the intonation point. Mark the intonation point with a really sharp pencil, then take the saddle out of the bridge, file the bone to the correct intonation point, and use needle files to blend the new bone into the old to make it pretty. This sounds kind of strange but it works fine. In fact, I’ve used this trick to correct intonation on a whole saddle, rather than to fill the slot and recut it to a more accurate position. It’s sort of an emergency measure, but in your case it should be perfectly acceptable if you make it pretty enough. ◆