We had a single bed in our guest bedroom and were looking for a solution to sleep two people that we could stack (the beds, not the people).
IKEA sells stackable bed frames but they are rather flimsy, a bit too low and come with very thin mattresses. Inspired by IKEA's design but with a few enhancements, these frames should last a lot longer. Everything is joined using wooden dowels.
I started from some leftover pine SLS beams.
On the table saw, I cut out a groove for the slats to rest on.
Set up the router table to drill the holes for the dowels more accurately as I didn't think I'd be able to do this with a simple hand drill. Not ideal as I didn't have the correct bit, but I went slowly and it worked out fine.
The legs with the holes for all the dowels.
Dry fit looking good.
Made holes and feet in the legs to make them stackable.
Routed out a handle in the headboard and glued it to the legs.
Full glue-up made me realise my clamps were not long enough. Only the hundredth time this happened to me.
I screwed the slats to the frame, what are you going to do about it man.
Well, they fit next to each other.
And they also fit on top of each other, mattresses included.