Glued Mortise and Tenon Joint

[Maple Mountain]

Hello.  I need to do a neck reset on an antique parlor guitar with a tight, glued mortise and tenon joint.  Has anyone separated one of these joints?  

[Leonard McCoy]

It's done basically in the same way as with a dovetail neck joint. Heat the fret tongue until the glue releases, then loosen the neck joint by injecting steam. Don't forget to loosen the bolt, too, inside the guitar that secures the neck. There should be plenty of resources out there describing the process in great detail.

Edited August 23, 2019 by Leonard McCoy

[Maple Mountain]

Thanks, Leonard.  This one will require a different approach from the dovetail.  I've steamed off plenty of dovetail joints.  I can see this joint clearly because I have the back off the guitar.  The mortise measures 5/16" wide by 1/2" deep and extends into the neck block to half way between the 12th and 13th frets (the guitar is 12 fret parlor from the early 1900s, probably made in England).   The neck joint has no gap as there is behind a dovetail, and drilling into the 13th fret  would take me into the neck block, so it's a good thing I removed the back.  The joint is perfectly fitted, so the only thing I can think of so far is to drill deep holes into the neck block exactly at the inner corners of the mortise and put little shots of steam in to avoid backpressure issues.  If the heel is glued to the sides, that will introduce another challenge.  I'm not concerned about finish damage, as it's French polished, so I can repair that easily.

I'm hoping another member has been down this road before.