Q: I am still pondering what to do with my '77 Mossman Southwind - you looked at it at Winfield 2 or 3 years ago and we talked about what to do with the neck and frets, etc. Currently, I think what the old box REALLY needs is a throughcut saddle- the current one keeps wanting to lean toward the sound hole, and I am thinking about routing a new (and, if needed, slightly oversize) slot and putting a longer saddle. Then I'm told that oh no, that might split my bridge. I initially wanted new frets- maybe I should get new everythings.
A: Before modern router technology, the only way to cut a saddle slot was with a saw. Having supporting wood around the ends of the saddle is vastly superior to a cut through saddle. If your saddle is leaning forward, it is either loose in the slot, or the slot was routed wrong. Neither flaw would be cured by a cut through saddle. Martin makes imitation old cut through saddles on their vintage series guitars.
To keep the front of the bridge from breaking off, and saving production time, the saddle is glued in. They glue the saddle in while they are machining the bridge blank. When they cut the bridge foot, it also cuts a perfect fit on the end of the saddle. With a routed saddle you can pull it out, sand down the bottom (not messing with your compensated and polished top), shim it up with hard wood, even cut down the bridge top if necessary. Cut through saddles can only be filed down, or routed out and replaced. S L. Mossman guitars never had cut through saddles. Stuart may have done one or two as he was figuring out how to make a guitar, but they were never used in production.
A 1977 Mossman is now 33 years old. Under normal use it should have had at least 9 action sets, two or three refrets, and a neck reset. It is most likely due for a trip to the luthier, but not to get a cut through saddle.