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Glueless joints for making posts

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Windows

Old Oak
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Have any of you seen interesting glueless joints for making posts from two thinner pieces of wood (example: joining two 2x4s to create a 4x4)? Joints do not have to be reversible/dismantlable.

More specifically, I am going to be creating bench/table legs and quite fancy some chunky ones. Currently considering to join them by doing bow tie at top and bottom of the legs with the rail being a through tenon with forked wedge (rail does need to be detachable). Leg length is less than a metre.

Alternatively could do sliding block keys where you cut big hole-little hole, and a key with ends sized for the big hole and middle bit sized for the little hole, insert key into big hole, slide it towards little hole, add another block into the big hole to lock the key in place, then the other piece to be joined also has holes, you line up the big holes with the keys then slide the entire piece to lock it together.

Anyone got others they like?
 
Could I ask why you wouldn’t want to use glue?
If you go down the bow tie route what will hold them in long term?
 
There's probably some clever Japanese option but here are a few thoughts to add to the options.

Have some short horizontal pieces at top and bottom. Cut mortises in them. Make tenons at either end of your half-thickness legs and fit them into the mortises. Secure by pinning/draw boring.

Cut a long tapered sliding dovetail on the inside faces. You'd lose some thickness but in hardwood that could be as little as 6mm. The joint would be entirely hidden, which might somewhat miss the point of not just using glue.

Lay your demi-legs together and bore round holes through. Fix through with tight dowels. These could be thin "wooden nails" (eg bamboo skewers) and could be at different angles so they don't pull apart You could use thick dowels and add wedges in the ends. Or cut threads on them and add decorative nuts/knobs.

You could use the old technique of "secret screwing" which used to be used for things such as fitting polished skirting boards.

One demi-leg has two woodscrews inserted, but protruding by about 8mm, on what will be an inside face. The other one has large holes bored, 8mm deep, diameter same as the screw heads. Cut slots, 10mm long, same width as the screw shanks, in line with these holes, off to one side.
Fit this piece over the other one, so the screw heads go into the holes. Knock the ends so they slide along, with the screw heads crushing their way along underneath the grooves.

Or you could just screw the halves together in the usual way. ;)
 
Windows":3cqjfkbf said:
......Alternatively could do sliding block keys where you cut big hole-little hole, and a key with ends sized for the big hole and middle bit sized for the little hole, insert key into big hole, slide it towards little hole, add another block into the big hole to lock the key in place, then the other piece to be joined also has holes, you line up the big holes with the keys then slide the entire piece to lock it together....
Click to expand...

Sometimes a quick sketch is much better than a lot of writing! :)
 
Why not use glue:
1. It’s dull and doesn’t give much opportunity for structural aesthetics (I like to see joints sometimes)
2. I tend to avoid chemicals of all sorts for health reasons (this isn’t an absolute position, I have glue and I use glue sometimes when I feel it’s worth it)
3. What if I change my mind about how I want to use this wood - wood is a limited resource. Although I’m not too worried about reversibility in this case, I always consider it. Glue complicates reversibility. (Just like cutting wood does - but the glue is optional and the cutting isn’t)
4. The act of designing/creating without glue amuses me
5. Sometimes I don’t want to wait for glue to dry
6. Suspect I can get away with rougher surfaces at the joined faces with a wood joint than I would feel comfortable with a glue joint. Laziness or lack of confidence? You decide.

I should have also said I was trying to avoid metal fixings too based on points 1 & 4 in this list.

What would hold the bow ties in over time: the table top and the floor (and gravity for the top one)
 
You’re right Mike. If it helps, the keyed block thing I was trying to describe is the same as the secret screwing technique Andy described except that instead of a screw you use a wooden key so you have to create mortises on both pieces for it to slide into.
 
Thanks Andy. Yeah, sorry, I forgot to mention no metal. The secret screwing is a great technique though. I was attempting to describe the wood-only version of that. Cap & foot either tenoned like you suggest or perhaps dovetailed could be a good option too thanks for that and for the angled loose tenon/dowel suggestion. Really appreciate it.
 
In thinking about Andy’s long sliding dovetail, I thought what if it was a loose batten to preserve leg thickness, and what if it was only at the top and bottom to preserve material and save work, and I ended up at bow ties again. Turns out every joint is the same, only different.
 
If this is for a table and there are stretchers, you could use something like this to hold the leg parts together. You can make all sorts of decorative variations, shaping the tenon tip and wedge, swapping the tenon to be horizontal not vertical, etc. And possibly do something similar with the rails at the top.

IMG_20220911_091753892.jpg

Or is this what you meant by "forked wedge"?
 
Surely using glue is more reversible than any other mechanical way of fixing the two pieces together? You can run a saw down the glue line and remove the absolute minimum required to split the posts back apart but if you do it mechanically you’ll be putting mortice holes, key holes, bow ties, or whatever else to hold them together which will effect the reusability of the timber?

If you’re worried about chemicals use a pearl glue, about as natural as you can get.
 
Great comments & questions. Thanks!

Regarding why not buy larger wood, the answer is fairly straightforward: I’ve already got these sizes, so anything else would be additional expense. I’ve noticed though that larger sizes are sometimes more than 2x the equivalent small size, so that might be a reason why I would choose a smaller size and join it in the future. Just seems like a useful capability to have really. But, if I valued my time more and my cash less, just buying a bigger size would be the perfect answer and the right thing to do, so thanks for mentioning it.
 
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