Previously I had made a set of trestle table legs based off of the surviving examples in the ‘Onze Lieve Vrouwe ter Potterie’ museum in Bruges, Belgium based off of an article and pictures found on the St Thomas Guild website. I suggested a few different options for table tops and finished that project. This is part two of the build. A table without a top is not particularly useful.
Looking around and doing some light research I came up with three options that I explored for historically plausible table tops for my project. I could go with a slab, framed, or breadboard top and still be relatively correct for the project
A slab top is just what it sounds like, a large, thick, heavy slab of wood that has been flattened and cleaned up to use as a table top. This is a relatively simple approach but it does present several problems for my purposes. We know it was a practice for a long time to use such a table top, not many survive but we have enough evidence that we know it happened. For my late 14th century portrait it would have been a little out of place. More importantly it would be both very heavy, and very hard to find.
In modern times you can find large slabs of lumber, several inches thick thirty plus inches wide. But to do so you either need to find and mill it yourself, or pay a lot more than I am willing to pay. In addition as I said, it would be very heavy due to the thickness. For this type of table top you need that thickness, Such a large piece of wood needs that thickness to stay stable and not suffer significant movement due to surrounding atmosphere. Not that it won’t move, but it’s mass means even if it moves it will maintain functionality. A thinner board of similar length and width will be much more prone to checking, twisting, and bowing.
A second option and the type that is paired with the Bruges trestle in the museum is a framed top. This is a series of boards laid parallel and then incased in a surrounding frame with mitered corners. It is difficult to know exactly how the surviving top is constructed so we can only look at the outside evidence and extrapolate. The existing piece has what appears to be two boards set inside the outer frame, each one is then pegged through its shorter side to the frame. How the sides are connected is not as clear. Glue is possible but seems unlikely that it would have survived so long without a glue failure so a mechanical joint seems likely.
One nice thing about this style of construction is it allows you to incorporate cheaper means such as utilizing plywood for the central section since there will be no exposed edges.
Connecting the central boards to each other as well as the side rails can be accomplished in a number of different ways modernly, the quickest and easiest would be with a biscuit jointer. It is not something that will ever been seen again so ultimately the choice is up to you and your personal preference. For a more historical option you could try one of two options, a tongue and groove of a spline. At the heart of it a tongue and groove and a spline joint are the same, the only difference is that a spline is a separate piece of wood that fits into parallel grooves in both pieces instead of an integral tongue on one board.
Once that is figured out you can glue up your center boards and measure for your frame, the corners of the frame are a mitered corner and the original shows dowels on both sides of the miter joint, suggesting that there is a hidden tenon or spline connecting the joint to make it stronger. No sign of a spline or tongue and grove connection shows on the end and if it was a mortise there would be no need for pegs on both side.
I ultimately chose to use a breadboard end table top. My top is made of red oak to match the existing legs. Some furniture you can use a softer lumber to save weight and save money but for a table top you need to consider how it will be used. If you are always going to have a table cloth on it, the top can be a slab of plywood and call it done, the cloth will hide it, a couple coats of sealer to prevent delamination and you are ready for feast. If you will not be using a table cloth or not all the times, avoiding the exposed plywood is good. You have gone to all of the effort to make a period trestle, what’s a little more work.
I made my table top based on my existing tables as they are the perfect size to fit neatly in my trailer and as I phase them out to more accurate examples all of my arrangements have that size in mind. If you are not sure how big to make your top, compare it to your modern dining table and decide if it needs to be a different size.
I had to do a bit of searching to find my lumber for the top, during the fall of 2020 lumber was not getting to the stores as well as it had been so sometimes it was a question of buying what was on hand and waiting until more showed up to be able to finish a project. I ended up searching several stores due to inability to find the correct amount of lumber in the right length and width and even then I changed my set up to accommodate the lumber I could find.
I was starting with presurfaced boards so my first step was to rough cut to length and then joint an edge flat. Once I had a flat edge I ran the board through the table saw to bring it to width. With the advantage of modern glue and a bit of impatience to get going I skipped using any jointwork and instead just butted the boards together and glued. If I was to do it again, and I need to make a couple more down the road, I will most likely use spline joints for the top for that extra bit of security. I glued and clamped the boards together, making sure to get it as flat as possible, with these longer boards slippage was a concern and the flatter I can glue it the less work later on.
When the boards were dry I used a circular saw to square up the ends and cut it to the final length, tenons included. You can just as easily use a hand saw to cut it off but I was impatient and need to get my crosscut saws sharpened. When I had my ends to length and square I marked back one inch from the edge and used a straight edge to make a fence for my router. I trimed down one both sides and both ends so my top have a half inch thick one inch long tenon sticking out.
Once my tenon was cut I measured my final width for the top and cut a pair of end boards to match. Setting my table saw blade to protrude a little less than one inch I began cutting the mortise in the end board, flipping it end to end to make sure the mortice was centered in the board. I intentionally cut the mortice to narrow and then snuck up on the proper width for a snug fit. When I got close I instead went to the tenon and paired it down as needed for the fit. For this type of end a snug fit is important the joint is exposed on the ends so gaps are noticeable but more importantly if the mortice is loose on the tenon it would function as intended to help keep the top flat and tight.
With the end fitting snugly it was time to lay out the dowel holes. My top ended up useing six boards five inches wide. One of the purposes of the breadboard end is to allow for expansion without cracking. To accomplish this the middle two dowels are set into the two center boards snugly, while the remaining dowels are tight through the end, but have some side to side play in the tenon. Looking at the dowel holes with the end off the center ones are round while the next out are slightly oval, and the furthest out even more so. A large degree of play is not needed here, perhaps a sixteenth of an inch per board.
When the holes are done it’s time to glue up the ends. You will only put glue on the tenons between the two center dowels, and one the dowels themselves where they go through the ends. This allows the table to expand as needed. One of the tricks I have found over the years is you can peen the end of your down with a ball peen hammer to make it mushroom a little. This serves to help lock the dowel in place but also to make it fit the hole better if its a little irregular.
Once the glue is done you will most likely need to do some work flattening your table top. Remove excess glue, plane down high spots, pare your dowels flush to the top of the table. I used a combination of a scrub plane, a scraper, and a scraper plane to get my desired finish. You can sand the top but I personally love the look a planed finish gives to the project. I used boiled linseed oil to finish the top, to match the finish of the trestle. I still need to attach some battens to the bottom and drill some dowel holes so I can secure the top to the trestles but it is useable now.
Some considerations to make as you are working. Your table is a large piece that will be a center point of most camps. It will be moved about and abused as time goes by. Small touches matter. Chamfer the edges of your table a bit, this will make it much nicer on your hands but also reduce the damage your edges take from getting knocked around. Also chamfer the corners for the same reason. Condensation and hot containers can effect your table top a lot, use a good sealant even if you are going to have a cloth on it all of the time.
I presented a class on this project along with many others that you can check out online. If you have any comments, questions, or suggestions I would love to hear them. I like talking shop with other people and enjoy seeing what you are making.