Need help fixing cracked dowl pin holes

[Peter Christensen]

Looking at the OP's pictures I think the hole the tenon passes through was a little too big and the tendon too short. When the round wedge is driven in the tenon spread in the loose hole causing it to split as there wasn't enough wood to resist the spreading. So I would glue the tenon back together and glue a shim in the bottom of the square hole where it won't be easily seen to tighten it as much as possible. That should reduce the splitting forces on the tenon and it should last another couple decades. There isn't enough material for fastener reinforcing and to make another stretcher with a longer tenon wouldn't be your girl's work.

[Paul Bent]

I think part of the joy I see in that piece is what has happened with it over the years. If it was from my daughter to me, I would drill a small hole through both split pieces and simply baling wire it in a manner which would keep the pieces from opening more while keeping visible the life in her efforts.

[Tom Bender]

Unless it's falling apart, just leave it, it's part of the patina.

[Alex Burkhardt]

I would pull the pin, and get the stretcher on the bench. Clamp and Glue may keep it going for another several years.

A more drastic option would be to cut the tenon and replace. Any number of ways to mate up two pieces of wood. Drill a new hole for the tenon, etc ...

Lastly, maybe grab a section of steel strap with a diameter that matches the outside of that through tenon. Think the type of strap that that secures conduit to a block wall. Screw through into the tenon and it should provide some additional strength.

Good luck!

[roger wiegand]

Rather than trying to force the crack closed I'd widen it a bit with a saw to give a good glue surface and then insert a dutchman, maybe 3-4 mm thick to fill the space without stressing it. I suspect if you force it closed it will just pop back open again. Made from the same wood, matching grain direction, and with a little artificial aging it could be nearly invisible.