Joint suggestions for heavy Victorian table base rebuild?

[Anonymous]

A friend of our has a walnut Victorian table that years ago her parents had 'chopped' down to fit in a modern dining room. It lost about 30% off its width. Whoever did it made new end rails rather than chopping those that were in it (no idea why - perhaps he wanted some nice bits of walnut?). Now the lady wants those replaced with wider ones as her new dining chairs are 1.5" too wide to go between the legs at the end!

The existing rails have been fitted, I believe, with a mortice and tenon joint into the substantial legs (haven't dismantled it yet as I want to do the whole job in one go over one day). The legs are turned walnut, 6" square at the top and tapering to about 3" diameter over about 30", sitting on strong brass casters. It's all extremely heavy.

The new joints will have to be concealed, but above all very strong as the table gets wheeled around. It also expands out to almost 15 feet long (by 3 feet wide) - a true dining table. The new rails will be made from 4" by 2" walnut. I have two thoughts for the joints...

Alternative 1 is a large dovetail with the rails dropped in from on top. Perfectly concealed and the ultimate in strength. But difficult to make on site to ensure a really tight fit. Not hard to cut the rails, but getting a decent slot into the leg is another matter. And there are four to make!

Alternative 2 is another mortice and tenon. Nowhere near as strong as the dovetail, but still concealed. Easy to make on site, but could they take the stresses of moving such a heavy beast around, on carpeted floor at that? I should point out that there's not enough room to pin the tenon from the back (inside), nor can I damage the exposed surface of the legs by using some sort of fastener into the ends of the tenons.

Any other thoughts from the experts?

Thanks.

 

[The Restorer]

Go for mortise and tenons. Theres a good reason that they are called "traditional" if done properly they'll last far longer than anything else.
The trouble with the dovetail idea is, as you say, cutting them on site. Theres also the fact that unless the tails are quite long to extend deep into the legs theres a real change of failiure of the joint. Draw it out full size on a piece of paper and look at the weak point at the neck of the dovetail and, if the angles are quite steep, where the corners of the dovetail are.
You could always pin it from the outside with 6 or 8mm dowels, stagger the tenon to mortise holes slightly and you won't even need to clamp the joint . This is the traditional way of doing things and the pins should sit about there widthe in from the mortise side edge. If you make the dowels with a dowel plate, they'll also have slight barbs on their edges that will hold them in.

 

[Anonymous]

Thanks Restorer. Unfortunately there's no room to pin the tails, although I could put something in from behind at an angle, perhaps. I'll see once it's in bits...

What do you think of putting the new walnut into a kiln for a while to get it really dry, so that when it settles in the joint tightens up even more? Chances are the wood is 'wet' anyway from being in store in the workshop that hasn't been used for months now....

 

[Chris Knight]

Brian,
Given the size you mention, I would think M/T should be stronger than a dovetail. As restorer suggests, a drawbored arrangement would be ideal - I can't understand why there is no room for this, can you elaborate?

I would also ensure that the wood you use is properly dry - and let it acclimatise in the same room or at least at the same humidity level as the table for a week or two if possible. I wouldn't fool around with moisture content as you seem to be proposing, I think you might easily come unstuck.

 

[Anonymous]

The problem with some sort of fastening on the tenon is that there is only about 1/2" of space to drill into the leg from the back, and I don't want to drill into the wood on the face. I think some screws up through the rails into the top should provide extra stability.