Now that I’ve got square pegs on the ends of the arms, I’ve got to make square holes for them to fit into. Wing Chun dummies have a pattern of two upper arms at upper chest height, and one lower arm at midsection height. Most versions also include a lower angled leg, but this isn’t used in my practice. I can always add it later. The lower arm sticks straight out from the midline, but the two upper arms are angled out toward the user’s shoulders. There are many variations of this, but the most common is about 9” of spread at the end of the 11” arms. The two arms have to cross in the center of the body, and thusly are set at slightly different levels so that the tenons won’t interfere with each other.
The problem with working with an irregular object such as a log is that layout becomes very difficult. My solution for determining arm angles was to make a pair of “dividers” out of thin strips of wood and nail it to the center point of the body. I measured out 11” on these and made a mark, and then spread them apart until these marks were separated by 9”. This then served as a layout reference for drilling and chiseling.
I started drilling with a 1½” auger bit in a 14” brace, but after getting the hole well established, switched to a Powerbore spade bit in my 5amp Skil drill for the majority of the work. I’m a tough guy, but I’m no masochist. If I had an auger with the long wooden T-handle I might have tried it, but that’s a lot of wood to remove by hand with a brace. Once the point broke through the back side, I switched back to the auger bit to from the outside ensure a clean exit hole. Once these two holes were drilled, I went ahead and squared them up before drilling the third hole. This way, I could center it between them visually, effectively negating any error in the mortise angles.
Drilling the holes was the easy part – squaring them up through 9” of oak was harder. My primary tools were a 1” Blue Chip chisel and a ⅜” Ray Iles pigsticker mortise chisel. Unfortunately, I didn’t have anything bigger for the brute force work, so I had to make do. I later ordered a 1” Sorby mortise chisel for the work on the frame, but that’s a story for another day. One trick for hand-mortising is to use a headlight to see down into the mortises for more accurate trimming.
Eventually, the log bore a striking resemblance to a Polynesian statue:
The next step was a pair of 1” x 2” horizontal rectangular mortises to receive the hickory slats that will support the dummy. This was more of a challenge than the arm mortises, because these had to be parallel and coplanar. The reason for this was that these slats would have to ride in slots in the supporting frame, which would naturally be parallel and coplanar themselves. This was complicated by the fact that, as you may have noticed, the log is both irregular in shape and curved. To achieve the desired line for the front of the dummy, I was going to have to angle the line of the slat mortises relative to the apparent centerline of the body.
Not so easy.
The first step was to place an arm in the lower hole and turn the body on its side to establish a horizontal line. I then set one of the still-attached wood strips at a right angle to the arm as a vertical reference, and a long flexible rule was used to lay out the approximate locations of the two slat mortises. The mortise was then drilled and squared up much like the arm mortises. Now for the real trick – aligning the second mortise with the first. I placed one of the 1×2 hickory slats through the mortise to serve as a true vertical reference, then re-marked the second mortise directly from the slat to ensure that they were parallel. Drilling and chopping were done with the slat still in place so that everything stayed lined up. When I finished with the mortise and inserted the second slat, this was the result:
Not bad, eh? Certainly within tolerances. The lower slat does have a slight twist, but nothing that can’t be compensated for by altering the mortise shape a bit. The nice thing about this project is that all the joinery is supposed to be a bit loose. The arms have to have a bit of wiggle room so that they can make a nice clear “CLACK” when struck properly (“CLUNK” if struck improperly). The slats should be a little loose in the body as well so that it can shift slightly when struck. Makes life easier when mortising!
And here we have the finished body with arms in place. You can see how the curve of the body altered the line of the slot mortises. This strange shape may actually have some advantages in practice by simulating the enemy’s forward leg. At least, that’s how I hope it works out. If not. I can always get another log and make the body again. Now that I’ve done it once, another would be no problem. However, no point in waiting for the perfect piece of wood – work with what you have now!
You’ll notice that the arms are just sitting in their mortises, waiting to be yanked out of the body. Since this is not their intended role, next time we’ll use some removeable wedges to secure them in place. Stay tuned!