Maple trestle table
The most important part of planning this project was determining how to manage the large 100 lb table top once it was glued up. So that led to completing the trestle first, then getting the top glued up, then fitting the base to the top. Here is how that went.
|Trestle before attaching to top.|
|Planes used to flatten top and underside on the planed surface.|
After surface planing I laid out the boards and selected the best surfaces for the top, laid them out in the final order (straightest, cleanest grain on the edges of table top to minimize edge finish and splinter issues), flipped every other board for alternating grain, and marked them. Then I planed one edge straight on board #1 and then the matching edge on board #2 and so on until all were fitting with minimal gaps and ready for glue.
|Underside of top during final planing.|
The plan was to plane the bottom flat, cut in the recesses for the tops of the trestles, locate and drill the top for the clamp blocks (to attach the top to the trestle), trim the ends of the table, bevel the edges, then flip the top over and finish plane the top. Finish of satin polyurethane would then be brushed on, sanded with 320 grit between coats, then another coat - 3x. That is how it went. Mostly.
|One of the recesses for the trestle.|
This is common a lot of places but I have not seen as rapid changes as I see on the west coast - Santa Ana winds one week, fog and no sun the next. The biggest issue was creating a flat table top and then finishing it during the rainy season. I had to apply 3 coats of polyurethane to the underside of the top, wait for it to dry and toughen up before flipping it and sealing the other side. During that drying window we had a very wet week and the top took on moisture on the unfinished side, so it cupped about 3/8" across the table. So I sealed the top side and waited for the moisture (now trapped) in the table top to become uniform within the table top so it would flatten back out to its original flatness. This took several weeks inside the house.
One interesting part of the project was creating the through mortises for the uprights. These four mortises were first roughed out with a power drill by drilling down from each edge and meeting in the middle. The cleanup was done with mortise chisels and then with paring chisels. I made a block that was the thickness of the finished walls of the mortise and used it to rest the paring chisel on for the final cuts. This ensured that the walls were parallel to the outside faces, which is fine so long as the workpieces have parallel faces. The four mortise and tenon joints were then pinned with 3 mulberry pins that were driven into the offset through mortises (offset to tighten the joint when the pins are driven in).
These were shouldered through tenons that had to be laid out and cut carefully to avoid gaps. I used a marking knife to do the layout and preserve a precise line around each piece. The layout was done before the taper cuts were made to the uprights, or at least it was easier then. After pinning, the protruding tenons (and pins) were later cut off with a flush trim saw and then planed lightly. No glue was used on the joints.
|The leg assemblies, wedges, and clamp blocks during finishing.|
Again, the finish was 3 coats of Minwax Satin Poly that was brushed on and sanded lightly with 320 grit between well dried coats. I put the first coat right on the planed wood, no sanding. This process seems to work well with the oil-based poly. Any drips or accumulations of finish that you do not want made a permanent part of your piece can be scraped down with a sharp cabinet scraper before the next coat - and don't make your trestle joints too tight if the surfaces are going to get a build up of poly or varnish, because these finishes add thickness to the material.