3-way Miter Joint, Chinese Style
I had to do it….. after attending the Williamsburg conference “Working Wood in the 18th Century”, I rushed to the computer to figure out that beautiful, interesting, complex, and strong 3-way miter joint. This was presented at the conference by an excellent craftsman, Andrew Hunter. Even after watching his careful layout and precision tool work, I was mystified about the joint details. I’m not sure that I’ve done this precisely per Andrew’s design, but I think it works.
Note: The steps shown are those used in SketchUp. The actual work in the shop would require a different procedure.
Step 1: Create the three pieces (components), Post, Front, and Side. These are all 2 1/8-in. square stock. The top pieces are mitered.
Step 2: Turn around to the rear view and create the mitered peak (1/4-in. thick) on the post. This will require the Line and Push/Pull Tools, and also the Intersect function.
Step 3: Connect the three pieces and trace out the mitered peak lines on each of the Front and Side pieces. I use X-ray view to accomplish this.
Step 4: After doing step 3, you should see the additional lines shown below on the copy of the Side component. With the Eraser Tool, remove the waste on the front face of the Side. Do the same operation on the Front piece.
Step 5: After Step 4, you should have components that look like this…..
Step 6: Now orbit your view to a rear view of the joint. Then add the tenons to the Post. Dimensions are shown in a later view.
Step 7: Re-connect the three pieces, and trace over the tenons to make the mortises in the Front and Side pieces. Use X-ray view.
Step 8: Orbit around to the front of the joint. Review the X-ray view to see if everything fits properly and that there are no collisions of the joinery.
Step 9: Here’s the assembled joint using the Back Edges Style. Save as a Scene.
Step 10: Make an Exploded View with Back Edges and save as a Scene.
Step 11: This is a detail dimensioned perspective of the top of the Post.
Note: These are my dimensions and may not be exactly those used by Andrew.
Step 12: This is a dimensioned perspective view of the Side.
Step 13: This is a perspective dimensioned view of the Front piece.
Step 14: Of course, I would make a bunch of orthographic templates in X-ray or Back Edges, and use these to help with the layout in the shop. I would have a top and side view templates for each of these complex pieces. I would not rely on the templates for accuracy of my knife joint lines, but they would help prevent me from making mistakes in the layout.
The above steps are an appropriate way to create these pieces in SketchUp. The procedure would be quite different in the shop. But now that I understand the joint, I can easily produce a step-wise procedure in SketchUp that would coincide with the actual wood.