Thread: Big Round Mortice and Tenon Joinery for Knockdown Bunk Bed

It looks alright to me. I like that you could make top caps for the tenons so you can set 'em up as two singles without too much hassle.

Originally Posted by rogerwilco

Personally, I reckon it'll be absolutely fine to just sit on top without any fasteners. Especially if I get a nice push fit like I did in the test.

I suspect it'd be a good idea to make allowances now for some sort of fastener, even it's just an ugly old screw. I don't know about your kids, but I remember lying in the lower bunk and "ceiling walking" on the top bunk to annoy my younger sister. I never actually popped the top bunk off the legs, but dang I came close a few times...

ie. better safe now than sorry later.

Originally Posted by Skew ChiDAMN!!

It looks alright to me. I like that you could make top caps for the tenons so you can set 'em up as two singles without too much hassle.



I suspect it'd be a good idea to make allowances now for some sort of fastener, even it's just an ugly old screw. I don't know about your kids, but I remember lying in the lower bunk and "ceiling walking" on the top bunk to annoy my younger sister. I never actually popped the top bunk off the legs, but dang I came close a few times...

ie. better safe now than sorry later.

Two really good ideas right there. The integrated ladder and the railing on the top bed could look potentially odd when beds are setup as 2 singles. But the flexibility is good.
I reckon you're right about securing them together. It'd look good to do a through pin in brass that finishes flush to the face. I've got some ~5mm brass rod somewhere, which would do nicely. The fit would have to be perfect, or it could look silly. And drilling the hole would need to be dead nuts accurate and square. I'd probably do with the good old mirror trick, drilling from the outside-in on both side for clean holes.

Good one!

Lot of time spent mucking about with cut tenons. Would be quicker to bore both pieces and cut up a broom stick to make the tenons. Can be glued into the bottom leg if you want but not really necessary and becomes a problem when the beds are to be used as singles. Receiving end of the tenons need to be domed to help with alignment when the beds are being stacked. When beds are single, remove the broom stick (if it hasn't been glued) and fit the end caps of your choosing.

Another good idea!

Can do that on drill press or lathe (parts are too big), So it's a plunge router and template (25mm max depth), or a forstner in battery drill. That's possible... but I reckon it'd be difficult to get straight holes that are also very snug fit for alignment.
Then again, I managed it fine when boring 19mm dog holes in my workbench, so... I suppose I could also turn some dowel to be just the right fit. This option has definitely got me thinking... Thanks Rusty!

There is no advantage sinking the dowel further into the timber than necessary. Keep the boring shallow and any deviation from exactly plumb would have minimal consequence.

Just thinking if I want to secure the joint with brass pins to stop any accidents, then 38mm (1 1/2 inch) round tenon glued into the bottom post is probably the go.
Once they're all fitted, then dry fit and clamp it up for alignment before drilling for brass pins.

I think you're right mate. This would be faster and simpler. Therefore likely to be better and more accurate, as there are fewer opportunities to stuff it up.

I wouldn't pin them. Cut your round M&T as per test pieces. Add a dowel a decent length into each for safety. Can be a bit of steel pipe or similar. Bore for the dowels by making a guide on the lathe that locates using the M&T. Make some caps as per Skews suggestion for use as singles. Even if the top bunk gets lifted via sibling annoyance it won't fall because of the Safety-Dowels (Safety-Dowel is a copyright of NCArcer Inc. )

WARNING WARNING
just a heads up keep them as single beds, there is nothing more exciting after a nice nice in bed with the bride than a 5 year old screaming from top bunk at 11.30PM

Daddy Daddy Iam going to be sick you leap out fly into their room just in time for her to throw up all over you.

I speak from practical experience and that was 35 years ago.

suffice to say they had single beds the next night.