As I mentioned last time, the dummy arms require some mechanism to hold them in place, while at the same time allowing them to rattle when struck. The traditional way of doing this is wedges or pegs that fit through the tenon a short distance from the body of the dummy. I chose wedges, primarily because I had a better idea of how to employ them.
I inserted the arms in their mortises, and measured the clearance from the body on the back. I decided to start the wedge mortises about 2” from the end of the arms. These mortises would be ⅜” wide, and 1” long on top, tapering to ¾” on the bottom. The width was based on the width of my mortising chisel, and the length was purely arbitrary – it just looked right. This was laid out on the top of the tenon as shown at left.
I then drilled a starting hole near one end of the mortise and chiseled out the waste. Yes, it looks like I’m drilling at an angle, but this is a posed shot. Try working a camera and a brace at the same time! The chisel is one of the wonderful English-pattern mortise chisels (pigsticker) made by Ray Iles and sold by Tools for Working Wood. I first made the straight mortise section, then angled the sloped section to match.
Next, I turned my attention to the wedges. I wanted a wood that was strong, but had some compressibility to hold in the mortise. I had a piece of soft maple left over from another project that was too small for anything else, which made it perfect for this. I planed it down to ⅜” thick, and cut wedges to match the mortise. As you can see from the picture on the left, I measured a 1 ½” span in about the middle of the wedge blank, and marked it at 1” on one end and ¾” on the other. This gave me the slope of the wedge. I let it extent about an inch on either side of this, but a bit more at the top, since repeated removal and replacement will probably make the wedge migrate downwards somewhat..
And above , you see the arms installed with the wedges in place. Because of the irregular shape of the log, I had to trim the front of two wedges back at a bit of an angle to give the required clearance. That’s okay, because it gave me a chance to fine-tune the action of the arms.
The next step will be construction of the frame. We’re getting into the home stretch here, and after all these strange shapes and hyper-deep mortises, it’ll be nice to get back to some classic joinery. Stay tuned!