# How would you join three pieces of wood, all at 90 degrees from each other (like 3 axis in 3D)



## jadenorth (Jul 29, 2019)

How would you join three pieces of wood, all at 90 degrees from each other (like 3 axis in 3D)? I was thinking a half-lap for two (making an X) but was stumped by how to join the third piece (practically speaking, it'll probably be a half-piece going out one direction, and another half-piece going out the other).

See attached for an image.


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## DS (Oct 10, 2011)

This is bad design, in my opinion. 
The legs would be weakest at the point with the highest stress load.

I've seen it done with a square-tube metal bracket hidden inside the joint with mortises.

Otherwise, the leveraged forces are tremendous on what becomes a very tiny stick of wood passing through the joint.


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## MrRon (Jul 9, 2009)

It could be done with a half lap joint followed by a mortise and tenon, but it would be very weak.


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## jadenorth (Jul 29, 2019)

For a half-lap with mortise and tenon, what minimum thickness for the tenon would you recommend? Thicker legs aren't a problem.


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## Sawdust35 (Jan 15, 2016)

Canadian Woodworks makes a table called "Ashterisk". 



While incorporating their leg design will alter your plan, it could look very similar.


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## SMP (Aug 29, 2018)

I've only seen it done with a block that I would best describe as an upside down "pyramid" that had grooves cut in on each side that the legs slid into, that rested just above that center connection point.


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## Ocelot (Mar 6, 2011)

Look in a Japanese joinery book. They excel at that sort of thing.


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## PPK (Mar 8, 2016)

> This is bad design, in my opinion.
> The legs would be weakest at the point with the highest stress load.
> 
> I ve seen it done with a square-tube metal bracket hidden inside the joint with mortises.
> ...


+1


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## jadenorth (Jul 29, 2019)

Found an example online. Do you think, with legs this thick, a half-lap combined with a mortise and tenon joint would be strong enough?










https://www.article.com/product/1928/trina-walnut-dining-table?forceCurrencyId=1&artcl_campignID=900506311&gclid=CjwKCAjw98rpBRAuEiwALmo-yvLNgYQHgrSmAuH73gLPiYZP5e7c0mUbtky5ZwSAOrozIADTJQp7EhoCzMcQAvD_BwE


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## CaptainKlutz (Apr 23, 2014)

LOL, for that design to stand up to my family, it would have be made of 2 inch square metal tube with 1-1/2 inch thick polycarbonate top.

With wood; legs would need to be 6 inch square, using half lap, plus 3 inch OD dowel 1 foot long attaching both halves of the 3rd leg. I'd probably have to fix it after a few years by adding a triangular hoop mid way around the the top and/or bottom to limit the spreading force when 250 pound, 6' 5" teenager accidentally lays across the table top. 
YMMV


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## AZWoody (Jan 18, 2015)

> Found an example online. Do you think, with legs this thick, a half-lap combined with a mortise and tenon joint would be strong enough?
> 
> 
> 
> ...


It looks to me like it's 6 pieces of wood joined to some metal box with posts that go into the wood and epoxied into place.


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## MrRon (Jul 9, 2009)

Thinking about this some more, a half lap won't work because all surfaces of the joints will be 120° apart from each other.


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## corelz125 (Sep 23, 2015)

I agree with the captain make it out of steel tube.


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