Tuesday, November 20, 2012

Dining Table: Trestle Structure

The support trestle is all made out of old Douglas Fir framing lumber that came out of our house, which was built in 1911.  Roof rafters were 2 x 4 and will live on as the stringers and legs, a 6 x 6 porch post will become the feet, and a 2 x 6 joist from the bathroom floor will become the horizontal brace.

The stringers (aka battens) were made and attached several weeks ago, as I flattened the top.

Mmmm.  Lead-based paint.
The big post that became the feet was coated in nasty old paint, had a ton of nails in it, and has been sitting out in the weather for a couple of years.  Even in that condition, I couldn't throw out a big chunk of clear lumber like that.  First I pulled all the nails (one I couldn't remove got driven in deeply with a nail set) and used a thrasher ebay jack plane to clean off the paint and flatten the surface.  The wood was wet from a few rainy days, so it kept the lead dust down.  I cut off a couple of 26" lengths with one of my grandfather's old hand saws, and then ran those through the power planer to clean them up.  After deciding how to orient the parts to hide most of the defects, I used the band saw to rip down the foot blanks to 3-1/4" x 4-1/4" x 26".

Ah, the irony.  I'm not a masochist.  That stock is too long to crosscut on the table saw.

To make the curved shape of the feet, I spent some time designing patterns on hardboard, then used that to draw and cut a couple of test pieces on 2x6 lumber to show my wife and refine the shape.  Once I got to something we were happy with, I used the template to draw the shape on both sides of the foot, and then cut off most of the waste on the band saw.  I used a hand saw and chisels to make the sharp arrises where the flat top transitions to the curve.  A paring chisel took off most of the remaining waste, and then a little quality time with the oscillating belt sander smoothed things out.

Shaped Foot
The legs are glued up from two 26" pieces of 2x4, with a 1/4" strip of walnut between them as an accent.  Final blank size is 25-1/2" x 1-5/8" x 7".

Roughing out mortises at the drill press
I put a 1/2" x 1-1/2" x 6" mortise in the stringers.  I made one with a brace and bit followed by chisel work, but roughed out the second one at the drill press with a forstner bit.  The quality is the same, but the drill press is quicker.  The foot got a larger mortise, 3/4" wide by 1-3/4" deep, because there's a lot more to work with on that part.  Matching tenons were made in the leg blanks, cut close with the table saw and fine-tuned by hand.  I have a Lie-Nielsen rabbet block plane that is my go-to tenon tuner.  It can even be flipped over and used to clean up the shoulders if the wood is nice.

Cleaning up a bottom leg tenon with a L-N rabbet block plane.  Haven't cut the narrow shoulders yet.
The cross brace is just a 2 x 6, planed down to smoothness.  Big 4" x 4-5/8" long tenons were shaped on either end, fitting into 1-1/2" x 4" through mortises in the legs.  Those were carefully chopped from both sides, since the edges would be visible in the finished piece.  After fitting the legs to the cross brace, a tapered 1/2" x 1" (to 3/4") through mortise was made vertically through those for tapered walnut tusks to hold the assembly together.
Drilling for the mortise that will hold the tusk tenon (in background)
that secures the leg to the horizontal brace.
A few more details:  the ends of the horizontal brace's exposed tenons were rounded off at a 5" radius, and 1/4" was removed from the bottom of the feet to leave square pads on the ends.  Most edges were eased or slightly chamfered with a block plane, to prevent splintering and keep the incidence of damaged shins to a minimum.  The stringers and feet were glued onto the legs and that's all the permanent joinery on the base.  Bam.  Done.  Now these parts can get out of the way while I finish the top.

The big question now is, will I finish in time to use this table for Thanksgiving dinner?  My family's not coming up until Saturday, so I've got a couple extra days.