Attaching metal legs to a slab

No cleats should be glued across the grain.No no no!
What’s the Mc of the wood right now?
Is the slab flat now?
What’s the Rh of the environment your taking it to?
These things matter and it takes experience and luck to make the right decisions on how to store and handle the wood.
The koa I have worked was very stable but it was also dry.
15 inches is not very wide but you still need to allow the wood to shrink or expand.
Some slotted tabs in the corners of the stand and screws is one way.
Good luck.

-- Aj

I guess I should clarify, the cleats I was thinking of making would have the grain oriented in the same direction as the koa in order to restrict movement as little as possible. Essentially they would have radial expansion in the same direction.

I don’t know the current MC of the wood now (picked up a moisture meter on Prime Day!), its been in my garage in a RH of ~10% for several months now. RH of the Dallas area is between ~50% and ~80%.

-- Justin, California

I do think it’s better to go from Low Rh to high Rh.So that’s in your favor.
Allow for movement you cannot stop it.
Maybe I’m not understanding your plan.
If it’s been in your care for several months and hasn’t warped you should be golden.

-- Aj

You’ll need to let that slab dry for quite a while before working it. Make sure it is stickered properly while drying to avoid cracking and warping. Seal any exposed endgrain. I’ve heard horror stories of koa furniture ruined when shipped to dry climates.

-- Allen, Colorado (Instagram @bobasaurus_woodworking)

Jay, I might not be understanding this correctly, so ignore this if I am. I am picturing 4 metal legs that are not attached to each other in any way. If that is the case, just screw the legs into the bottom of the slab. The legs will move independently of each other, but will float with the movement of the slab. FWIW

-- Art

On my metal bases, I drill a 3/8” diameter hole in the mounting flange, then screw the base on with a pan head screw and a fender washer.

Plenty of room for expansion and contraction of slab tops.

Hope that helps.

-- Doubt kills more dreams than failure.

Allen: Luckily the koa was relatively dry when I bought it and had already been surfaced somewhat, so I don’t think I will have too many issues with cracking or warping (none yet anyways). I will definitely keep an eye on it and I will check to see what its MC is once I get my meter on Friday.

Art: The legs are actually two rectangles, one on the left side and one on the right. So simply screwing them in would restrict radial expansion.

For ease of disassembly and allowing movement, would threaded inserts paired with slots in the legs (perpendicular to the grain) be sufficient to allow movement? I think this is what Aj2 suggested, but with the addition of threaded inserts.

Thanks for all of your help!

-- Justin, California

See the tabs on this base.
The hole is over sized with a large washer on the panhead screw the wood will move as needed.
And everyone stays happy including Mother Nature.

If your base doesn’t have tabs add some L brackets from the Borg.And make the holes so the wood can shrink or expand in its width.

-- Aj

Thanks for the help, using the panhead screws and washers sounds like they will work perfectly. I’ll be sure to post some pics when the project is complete!

-- Justin, California

Yes, make 1/2” slots in the cross-grain direction in the metal attachment points. The fasteners in the wood will move as needed. Have fun with the koa. It’s a very brittle wood and I’ve had lots of trouble with tear-out.

The breadboard ends on my first dining table in Austin moved over 3/16” on each end during the course of the year!

-- You can't control the wind, but you can trim your sails