Domino for bent ladder

[Philr99]

I build library, loft and kitchen ladders. I have been looking at making a bent ladder, a regular wood ladder at 12 degrees with a vertical extension at the top. I've read a lot about joinery but I'm unsure of the strongest way to join the two pieces of a bent ladder. I'm guessing the bigger domino as the tenon pockets are deeper? Any guidance would be appreciated,
Phil

 

[Michael Kellough]

If a person will be depending on the vertical extension to keep from falling off the ladder there should be something much stronger than wood tenons keeping the joint together.

At least use steel plates bent to 12 degrees on the back side of the rails (mortised in) since that side would be in tension if someone pulled the extension towards them.

If you don’t want any steel to be seen (I think the aesthetic objection to steel would be offset by the reassurance and safety it provides) then use a pair of 1/2” steel rods as dowels in each rail. Or preferably both steel dowels and plates.

 

[Crazyraceguy]

I'm a bit lost as to a bent ladder? Do you mean angled?

From what I read, I'm assuming a 12 degree tilt, that has a mitered joint near the top, this angled portion then continues vertically?
If that is the case, I don't see why it should have to be any more complicated than a bridle joint. There is plenty of side-grain glue surface and that creates a lot of sheer strength at the moment of inertia.
Meaning that the force is spread out, rather than at a single point.

 

[smorgasbord]

+1 on the bridle joint. Super-strong and attractive.