Thread: How are these table legs made?

One method is to use off-set mortice and tenons.
Precision in stock preparation, joint layout and cutting is the key.

The Japanese have a name for the joint, but atm I can' find it.

Looking at the pic in the first link, it appears the section of leg that just reaches the top of the image is in three parts, the centre section from the joint to the tip is slightly lighter in colour than the rest of that leg. To my mind the give away is that the centre third is lighter than the two outer sections just beyond the joint and at the tip, and the colour change seems to follow parallel to the edges of the leg, fairly unlikely for a natural colour variation in a piece of timber.

I believe that the other two legs are a each a single section with a mortice cut in them that allows a leg to thread through another leg. The third leg which locks the joint together, is solid at the near end but shaped like a two pronged fork at the far end. This allows the prongs to straddle the second leg during assembly, and then an infill piece is glued into gap between the prongs of the fork to make that section of the leg appear whole. In this case the infill is slightly lighter in colour, but this is hidden fairly effectively as it is located between the top and the joint where it will be in shadow in normal use.

does this work?

Originally Posted by ian

does this work?

Legend!

Know what the joint is called?

Originally Posted by qwertyu

Know what the joint is called?

How about "get knotted" ?

Originally Posted by qwertyu

Legend!

Know what the joint is called?

Wooden cross puzzle.
https://www.google.com/search?client...w=1536&bih=750
W

Just to save on a couple of cuts, piece #2 doesn't need to have a T-slot, an L-slot would work as well.

Somehow I doubt that this puzzle joint solution would have the strength and/or structural integrity for use in the way pictured in the orig post. That joint will have to endure a LOT of leverage!

I'd imagine it was constructed more like this:
- the first leg is solid.
- the second leg has a slot in the middle sized for the first to pass through.
- the third leg is made in two halves, with cut-outs on one end of eqach half to fit around the 2nd leg.

Slip the 1st leg through the 2nd and pin in place. Place the 3rd leg in position and scribe around it so you can see where the actual contact joint areas are. Within those areas, drill a pair of holes through the 1st leg, one on each side of the 2nd leg, sized so you can pass long, thick wooden dowels through.

On each of the 3rd legs halves, drill the joint ends to accept the dowels, slip on and glue. The dowels are through tenons, as it were...

You'd need to be accurate in your fitting and have a lot of faith in both your glue and the cross-grain strength of the timbers used.

Mind you, it does look very, very nice. Still, I really don't think it would last long enough to become an heirloom piece, especially if kids are in the kitchen.

Originally Posted by Skew ChiDAMN!!

I'd imagine it was constructed more like this:
- the first leg is solid.
- the second leg has a slot in the middle sized for the first to pass through.
- the third leg is made in two halves, with cut-outs on one end of each half to fit around the 2nd leg.

Slip the 1st leg through the 2nd and pin in place. Place the 3rd leg in position and scribe around it so you can see where the actual contact joint areas are. Within those areas, drill a pair of holes through the 1st leg, one on each side of the 2nd leg, sized so you can pass long, thick wooden dowels through.

On each of the 3rd legs halves, drill the joint ends to accept the dowels, slip on and glue. The dowels are through tenons, as it were...

I suspect that only one leg is a single piece, with the other two constructed as two halves joined by loose tenons.
I also think that using tenons will result in a structure plenty strong enough to use as the base of a table.

How come we've gone from no cutting in half to cutting in half? To make it easier, faster/commercially sensible for the builder? Or is using long loose tenons stronger than the original diagram as there is more surface area for the glue (with long loose tenons)

How would one go about cutting the bottom and the top so they sit flat, parallel and level against the floor/ table top?

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Also, as for glue would you go wood glue or something else like epoxy?

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long loose tenons (or dowels) are relatively easy to set out and construct and can be glued with normal wood glue.

If you wish, you can cut a long off-set tenon on the ends of each half of Leg 2 which goes through a mortice in Leg 1 and is then glued into a corresponding mortice in the other half of Leg 2. (see attached)

As I posted earlier, I'm sure I've seen a Japanese variant that uses scarf joints and pegs to hold the joint together.

Remember, the joint just has to appear to be impossible to construct -- which is largely a function of how well the joint is made.

Originally Posted by ian

I suspect that only one leg is a single piece, with the other two constructed as two halves joined by loose tenons.
I also think that using tenons will result in a structure plenty strong enough to use as the base of a table.

Oh, I agree about the tenons. But they'd want some length ino the leg halves for lateral rigidity AND the joints want to be a good, tight fit. For a professional, putting small (WxL) but deep mortices into end-grain is easy enough (chisel morticer anyone?) but trying to do this by hand? I think an intermediate woodworker would have more luck with drilling; hence that suggestion.

I don't see any real benefit from cutting the second leg in half either. Not when simply slotting it does the trick and avoids the whole issue of having to rejoin it altogether. I also believe a slotted leg will have 2/3 strength, while a cut & rejoined leg will have <2/3 strength and maximising leg strength is an issue here.

The third leg would be treated in exactly the same way anyway, your method or mine, except for the whole dowel vs tenon issue.

Originally Posted by qwertyu

How come we've gone from no cutting in half to cutting in half? To make it easier, faster/commercially sensible for the builder? Or is using long loose tenons stronger than the original diagram as there is more surface area for the glue (with long loose tenons)

The diagram for the puzzle joint is clever, but doesn't have the strength you need in that situation. It'll always be a "weak" joint.

A structural component is only as strong as it's thinnest section - that's where it'd break - and in the puzzle each leg is scored down to only 1/3 it's width at the joint. So at best that leg only has 1/3 strength of what the legs appear to have.

The method we're discussing, incorporating tenons, will add strength to the cut sides so that at best that leg's joint will have 2/3 the strength of what the legs appear to have. You follow?

How would one go about cutting the bottom and the top so they sit flat, parallel and level against the floor/ table top?

Given a level floor and assuming the legs intersect each other perpendicularly, ie at 90degrees, (this can be changed but only makes things more difficult) then the tops and the feet should be cut at 45degrees along the width of the board. Even if they're not perfect, you can install (and I would recommend this even if it was perfect) small rubber buttons for the glass to sit on on the top and similar on the feet.

Originally Posted by qwertyu

Also, as for glue would you go wood glue or something else like epoxy?

Personally I'd use a good PVA. Probably Titebond III.

Thanks guys. How deep would you aim for for the tenons? Domino XL says 70mm (but is that 35mm per side?) Routers can do prob at least 70mm

Originally Posted by qwertyu

How would one go about cutting the bottom and the top so they sit flat, parallel and level against the floor/ table top?

Originally Posted by Skew ChiDAMN!!

Given a level floor and assuming the legs intersect each other perpendicularly, ie at 90degrees, (this can be changed but only makes things more difficult) then the tops and the feet should be cut at 45degrees along the width of the board. Even if they're not perfect, you can install (and I would recommend this even if it was perfect) small rubber buttons for the glass to sit on on the top and similar on the feet.

I'd suggest the method used to get conventional chair and table legs level.

stand the leg structure on a known flat surface, chocking any legs that are known to be short.
Place a pencil flat on top of a block of wood and go around each leg marking a line that is parallel to the flat surface. Trim each leg to the line -- which is probably best done by hand.

This method works even if, by design, the legs meet the floor at angles other than 45 degrees.

Turn the assembly over and chock the legs till the already cut surfaces are level. Repeat the block of wood and pencil process.