Maple trestle table



Plain and simple, we needed a larger dining table to replace our narrow, shaky, and small one. While the old one had a certain Tudoresque charm, it was not a fit for our decor (aka the other stuff I have made). A lighter color was requested and the options were quickly reduced to maple. Light in color, makes a solid table, should hold up well. Turns out it also makes a right heavy table. 

Dimensions are typical: 30" high, 40 inches wide, and 90 inches long. The top is 6/4 maple and the trestle parts are 8/4. Final thicknesses were about 1 1/8" for the top and 1 5/8" for the trestle parts. 



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. 
I made full scale drawings of the trestle parts and made scale drawings of the trestle and top - my usual practice. This resolves some aesthetic issues, but more importantly it gets you to confront how you are going to cut, join, and assemble the pieces. Much easier to work out problems on paper. It also gives you some useful templates that can help with rough cutout and layout. 


The most important part of planing this project was making things flat with no jointer. Not having a jointer means flattening (at least) one face of every piece of stock by hand. For this onerous task I made a 42 degree kanna dai (plane block) that would reduce the tear-out I was seeing with the usual 38 degree planes. It worked well with the maple, especially for the finishing cuts. Heavy cuts were out of the question with it (impossible to pull, still caused tear-out). 


Planes used to flatten top and underside on the planed surface. 
Going was slow. Pretty much I threw everything I had at it at various times. That includes an old Bailey 5 1/2 plane in good shape and a narrower No. 5(?), smaller kanna, cabinet scrapers, etc. A lot of hours later, I had 6 boards for the top ready to push through a small surface planer. 

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. 
I wanted to try out biscuit joints in the hope they would improve alignment and speed assembly of the top. I guess they helped but don't expect perfection. The process of gluing up the top consisted of gluing up 3 sets of 2 boards each and then gluing up those 3 formed sets into a single top. Took a week to get it all together (I waited 24hrs for each joint to dry). I then had to wait some more until I had a sturdy helper to assist me in flipping the top over so i could flatten (plane) the underside, which was planed first.  

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.
One of the issues with this project is that it took months and spanned our hot and extremely dry summer and ran into our extremely humid fall and winter months. My uninsulated garage is my workshop and you can predict that a big top of maple will be warping all over the place depending on the conditions. This requires a practice of doing all actions symmetrically on each piece of wood involved. Plane one side? Plane the other the same day. Leave it laying on the bench? It will dry or absorb moisture on only one side and warp. This happens very rapidly. Our days can hit 90 degrees and nights are close to 55. Every time you store a workpiece, you have to consider the way it will deform. 

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.
The top is held to the trestle with 8 clamp blocks fastened by 16 #12 wood screws. Not exactly a beautiful way of doing it, but it is solid and allows for some movement across the top and is not visible from above. I paid careful attention to the pilot hole diameter and thread engagement because I did not want sheared off screws or stripped holes. Do test holes to verify that things will work the way you want them to. 



Edge treatment for the top is a 30 degree chamfer on the underside and a 6mm round over on the top, done with a ginnan-men-ganna moulding plane (left). This is a lot easier on those forearms that may rest upon it and it softens the look of an otherwise very angular design. 
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. 



Comments

Jesse said…
That is beautiful and brilliant. Congrats on the new table (and the new 42 deg kanna). May they both last many years.