Trestle Table Connection Details

A discussion of joinery for attaching a trestle table top to the leg assemblies. February 8, 2008

We are making a dining table for a customer, library style. The material is old growth redwood. The top is 43" x 100" x 2" solid, one piece, no glue up, no knots, no cracks, slight checking on the ends. The legs are milled from old timbers reclaimed from a bridge. Everything is mortise and tenon joinery with square pegs (walnut) through the joint.

I plan on mortising the leg assembly into the top. I will be making the mortise into the underside of the table. 3/4" deep. Matching tenon on the leg assembly will fit loose on the length, 1/8". I plan on cutting a dado into the side of the leg assembly 3/8" deep x 1/4" on both sides of the leg. This is for walnut clips that will screw into the bottom of the table top and set in the dado. I plan on a good snug fit with no glue so the top can expand and contract separate from the base assemblies. Any advice would be appreciated. I'm always learning.

Here is a photo of the leg assemblies. Walnut pegs haven't been cut yet. The square hole in the small piece will receive the tenon of the stretcher (?) and will also be pegged with walnut.

Click here for higher quality, full size image

Forum Responses
(Furniture Making Forum)
From contributor J:
Sounds pretty good to me. I would like to see the tenons on the legs with a little more room for movement on a piece this wide. I would also consider one or two battens to help keep the top flat. You can fasten them with clips on both sides or screw them on with elongated holes everywhere but the center. If you are going to finish the table, both sides of the top should receive the same amount of finish to control moisture absorption and release.

From contributor A:
How did you mill that top? Planers wider than 30" are hard to find.

From the original questioner:
We have a 50"x100" Multicam CNC. We milled about 1/16 off of each side with a surface milling bit, then random orbital sanded. The top was very flat to begin with. We have milled a piece of maple for a mantle top. 18" x 138" x 3 1/2" thick. After glue up it had a twist to it. We shim it so the twist is balanced, mill off as needed to level, then spin it 180 degrees, shim it and level the side we just milled, cut away the same amount. The entire piece is now very flat and we ran it through the planer, milled side down. In 138" it was out of flat by less than 1/16.

From contributor V:
I'm not sure I follow how the trestle legs will attach to the top. I have done trestle type tables in the past and attached the top through counter sunk slots in the top of the legs. Could you explain your method again, as I am also always learning also?

From the original questioner:
The top of the leg has a tenon. We will machine a mortise into the bottom of the table top which will be 1/2" longer than the tenon, to allow for expansion and contraction. The clips will be snug to hold the top to the leg.