The WNY Haunters decided that we would build a leering prop as our group project at the gathering at my house in Penfield, NY on July 18, 2009. I was unofficially put in charge of getting everything ready for the project, so I decided to put one together ahead of time so that I could make sure I knew what parts were needed and had them on-hand for the gathering.
The base I used for the leerer was a piece of 2'x2'x3/4" plywood. After building one, I realize that 3/4" is probably not required. I suspect you can get away with 1/2" and maybe even 3/8" plywood. You almost certainly don't need 2'x2', either. A smaller piece should work. I suspect you could cut that in half and use that.
To support the vertical piece of PVC, I used a piece of 2"x3" that was about 22 inches long. 2"x3" is what I had available at the time, but I'd recommend 2"x4", as the pipe straps I used just barely fit on the 2"x3". The length of the board will depend mostly on the thing you'll be putting in front of this prop. To give the vertical board a little more support, I nailed a second piece of 2"x3" at the bottom of it. That piece was about 8" long. Then, I nailed the whole unit to the base. For additional holding power, you may want to use screws instead, but I didn't have any the right length at the time, so I stuck with nails. We'll see how those hold up...
The PVC I used for this project was 3/4" PVC. This seems sturdy enough to support a wig head, a mask, and a robe. If you'll be attaching something heavier, you might need to go up to 1". To hold the PVC to the board, I used plastic pipe straps, which, at least at the Home Depot near me, were found near the electrical PVC rather than near the plumbing PVC.
The "spine" and "neck" of the prop consists of the following parts, starting from the bottom. All are 3/4" PVC. The lengths of pipe will vary depending on whatever will be in front of the leering prop.
The mechanism consists of 3 arms. The first is a piece of 3/4" PVC coming out of the tee fitting. My piece was about 7 inches long. The longer you make this piece, the less motion you'll get in the prop. The second arm is the one connected to the motor. I used a piece of 3/4" wide, 1/8" thick aluminum flat stock. This arm could have been about 4 inches long, although as you'll see in the pictures and video, my piece is actually longer. There is extra sticking out past the pivot point. This extra is totally unnecessary. I just haven't trimmed it yet. The longer this arm is, the more motion you will get in the prop. Since the arm represents the radius of a circle, the amount of motion you'll get is about double the length of the arm. The third arm is simply to connect the other 2 arms. I used 1/2" PVC for this arm, but you could use either 3/4" PVC or aluminum if you want to. To figure out the proper length for this arm, place the motor where you want it and have the aluminum arm parallel to the 3/4" arm. Measure the distance between the ends of the two arms. This is basically how long the third arm should be. Give yourself a little extra to account for the material past the hole you'll drill.
I used 2-1/2" #10 (I think) bolts to fasten the arms together. I could have used a 2" bolt on the joint consisting of the aluminum arm and the 1/2" PVC, but I didn't want to buy a second bag of bolts, so I just used 2-1/2" for both. On the joint between the aluminum arm and the 1/2" PVC arm, I inserted a number of washers between the two arms to act as a spacer. This raised up the PVC arm so that it would clear the motor shaft. There is also a washer on the underside of the aluminum arm, and a washer between the 1/2" PVC and the nut (although it doesn't look like I had this washer when I took the pictures below). Similarly, on the joint with 2 PVC arms, there is a washer between the bolt head and the PVC, 2 washers in between the 2 pieces of PVC, and a washer between the PVC and the nut.
When I ran the prop for Spooktacular 2009, I had a problem with the mechanism. I used standard nuts on the 2 joints. Based on the direction the motor was turning, this caused the nuts to eventually get tighter and tighter. Eventually, the mechanism bound up and wouldn't move at all. A few turns with a wrench, and it was back in business, but it was still annoying. The solution to this is probably to use a nut with a nylon insert. I have not tried this yet, so I don't know that this will fix it, but I suspect it will.
The motor I used for this project was this one (wonder how long this link will be good). This motor is a good speed for this prop at 12V, was strong enough to turn the prop, pretty quiet, and at $2.99, was a good price. The hole in the motor's shaft is the perfect size to tap with a 1/4"-20 tap. No pre-drilling was required. I tapped the hole and screwed a piece of 1/4"-20 rod that was about an inch and a half long into it. To secure the rod, I drilled a 3/32" hole through the motor shaft and the rod and pinned them with a 3/32" by 3/4" tension pin, which I simply tapped into the hole with a hammer. The motor was fastened to the plywood base using 1/4" carriage bolts. I think they were 2" long. This will depend on the thickness of the plywood you use. I used carriage bolts because of their rounded head. These wouldn't stick out as much as a hex bolt would, so it worked fairly well even on a cement floor like my garage.
Here are a few pictures of the prop. Click on a picture to get a bigger version of it.
I have created a video of the prop in motion. It is 1 minute long and about 2MB in size. The quality isn't the best, but it should be good enough for you to get the idea of how it works.
Page last modified 11/09/2009