I’m currently working on a reproduction of a Butterfly Table, circa 1695. The original of this piece is in the Berkshire Museum in Massachusetts. Here is the SketchUp of the assembled table with folded down Table Leaves on rotating Wings.

This internal view of the structural assembly without the Top shows structural detail. Note the Wing situation with dowel connections into upper Blocks and the Lower Side Rails. Obviously, those Wings must rotate without binding at the dowel joints.

Here’s a view of the Wing showing the rotation axis of the two dowel ends. Of course, that axis must be a continuous straight line through the centerlines of the dowels.

This shows the Lower Side Rail that has the socket for the bottom connection of the Wing

And here is the top connection of the dowel at the upper Blocks that are connected to the top connection of the Wing.

Before drilling socket angles in the Lower Side Rail and the upper Blocks, I wanted a final check of the SketchUp Model to verify these joints were properly and accurately located in the assembly. Below you can see that I added a dotted line with the Tape Measure Tool. I simply double-clicked on the centerline of the socket in the upper Block. That produced a dotted line that continues right through the center of the socket in the lower Stretcher. This confirmed my location and alignment of the Block and Rail Sockets.

Having high confidence on the location and angles, I proceeded to drill the Wing and Rail Sockets as shown below.

My next step was to make a dry assembly of all parts. Then I inserted a long dowel in the Stretcher socket to see how it aligned with the socket in the Block. I was happy to see the perfect alignment.

I was then able to check the fit up and rotation of the Wings as shown below.

It is nice when things go together so nicely.

Tim

KillenWOOD

	Creating a “rule joint” on a 17th-century Butterfly Table While the rule joint looks to be quite simple, the details are complex, along with the positioning of the special hinges.
	Best photos for SketchUp When it comes to re-creating a design in SketchUp, perfect reference photos make all the difference.
	Multiple SketchUp views for help in the shop Tim Killen finds it extremely helpful in the shop to have multiple views of the components from different angles and positions.

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