How Would You Fasten This Joint?

[Ken Krawford]

You know the drill - someone hands you a picture or a link to a web page and says "Can you make this?". This bed loft I'm making will have a ladder instead of the stairs but I'm struggling with the best way to attach the front and back to the sides. The posts by the arrows are 2 1/2" square and the bottom rails on the front and back are 4/4 x 6". I think the top rail is 3/4" but am considering making it 4/4 as well.
Since this loft has to come apart, my initial plan was to use 1/4-20 threaded cross dowels in the rails with bolts connected through the posts. The picture suggests 2 fasteners in the bottom rail and 1 in the top rail.
Any suggestions would be appreciated.

[Sam Murdoch]

I would consider making up the upper bed platform and the rails as a group assembly with a 2x4 base that sits between the side walls on a 2x4 frame. You could then attach through the bed platform frame into the side walls with carriage bolts. The weight would be supported by the frame work at the top of the side walls. The carriage bolts would simply hold it altogether. The important thing is that the corner posts would not be continuous from the walls below to the top rails.

The rail system can then be made strong with good joinery and glue and mechanical fastenings. This could all be fastened securely to the platform frame with lags that would still allow the rails to be separated when needed. I think that this railing needs to be stronger than your proposed fastenings would allow.

This idea requires some redesign from the original but I think will be stronger and easy to disassemble.

[Art Mann]

I did a similar job once upon a time but I was fortunate to have the original piece of furniture to examine. The furniture company whose design I somewhat copied was called "This End UP". I think they are out of business now. Anyway, they used a pair of rather long (10" maybe) lag screws in the areas indicated by your red arrows. I copied their construction technique and so far as I know, 20 years later, the beds are on their second generation of kids and have not been repaired or modified. Having said that, if I had it to do again, I would probably use fasteners similar to what you are proposing. I might go from 1/4" to 5/16". The reason I would do it that way is I suspect repeated dis-assembly and re-assembly of the beds with lag screws would eventually ream out the screw holes and cause problems.

[pat warner]

Cross dowel/screw connections pull the assemblies together (tension), offer all of the shear of the screw, simplify the joinery and allow KD assembly. A cross dowel finder will facilitate the location of the cross-dowel-screw intersect.
I believe the designer had it right. Cross dowels are called for; maybe not with the exact nut you show, but one like it.

[Ken Krawford]

Thanks for the replies. Is there a consensus on how far from the end of the board the cross dowel should be inserted?

[Pat Barry]

I think you really are going to wish the front rail could be removed easily, ie, lifted out of a slot to provide access to the sheets and blankets in order to 'make' the bed. Otherwise, this is going to be a struggle each and every day. As it appears to be from the picture this is a near impossible task.

[pat warner]

At least an inch.

[Steve Rozmiarek]

I think you really are going to wish the front rail could be removed easily, ie, lifted out of a slot to provide access to the sheets and blankets in order to 'make' the bed. Otherwise, this is going to be a struggle each and every day. As it appears to be from the picture this is a near impossible task.

We got rid of one of those type of things for that very reason. Completely impractical.

[Ken Krawford]

That very issue entered my mind. This is for occasional use when my granddaughter has a friend spend the night.

I think you really are going to wish the front rail could be removed easily, ie, lifted out of a slot to provide access to the sheets and blankets in order to 'make' the bed. Otherwise, this is going to be a struggle each and every day. As it appears to be from the picture this is a near impossible task.

[Chris Friesen]

I built something similar. To make the bed I simply climb up on it. Of course, the main frame on mine is Doug Fir 2x8...it's going nowhere.

The tricky part is lifting my kid up over the rails and onto the bed when he's fallen asleep somewhere else.