Brick-laid Connecting Stretchers in SketchUp
Tim Killen demonstrates how he used SketchUp to help him create the curved stretchers for the nesting tables he's reproducing
I am reproducing an 1800 Nest of Tables. The original piece is in the New York Metropolitan Museum and was designed by the Adam’s Brothers. In the picture below notice the lower connecting stretchers between the Back Columns. These are greatly curved pieces to allow a compact bundling of the four tables.
As these connecting stretchers are very important for table structure, I wanted to make sure of their structural strength. While bandsawing the shape in thick lumber would be possible, the resulting short grain at the tenon ends would sacrifice that needed strength. Steam-bending could be a solution, however there is uncertain springback that would be unacceptable, as the configuration of the curve must be fixed and certain. I selected a brick-laid method of constructing these stretchers, to solve these problems and ensure that stretcher grain would be in the same direction as the tenons. Here’s a picture of the Bricks (the 3 layers, and 2 configurations) for one of the stretchers.
I used three layers of bricks with only two unique brick arrangements. These bricks were designed in SketchUp with the following steps. There is also a video of this process below.
Here you can see the resultant stretcher that is bandsawed out of the brick structure above.
To create the individual bricks in SketchUp, I set up a top x-ray view of the desired stretcher shape. Then with the Tape Measure Tool, created guidelines that would outline brick shapes and provide adequate width for final bandsawing. I created one layer of bricks, then structured the next layer with staggered joints.
Each brick is a component, and because of the symmetry, I can copy and flip to the other end. Below you can see one of the bricks that has been opened for edit.
From SketchUp, I made full size templates of all the bricks and the resulting shape for bandsawing.
Here is the bandsawing procedure, that is “nibbling” with a 1″ wide blade.
This shows one of the stretchers straight from the bandsaw. Rough filing and scraping smooths it quickly.
Here is the status of the Nest of Tables. More inlay work to do on the Tops, then into the finishing process.