In this Instructable, you will learn to make movable, lockable joints for Halloween prop limbs. With this you can make your own skeletons, and with some extra work, a massive monster freak like this guy!
Step 1: Tools and Materials
1 inch shc 40 pvc pipe
1/2 inch sch 20 pvc pipe
1/2 inch fittings
6-32x1 1/2 screw with nut
8-32 set screw
1/8 inch rod
5/8 inch long nylon spacer
1/8, 9/64 inch drill bits
alen key for set screws
Step 3: 2
Mark on both ends where the shoulder on the inside of the fitting is that stops the pipe. Make another mark, 1/8 inch from the opening, all the way around on one side. On the opposite side, mark the end with two lines that just touch the opening of the fitting and are parallel. If using an elbow fitting, draw the lines on so that when the fitting is resting on it’s side, the lines will be horizontal (I did it wrong in the photo).
Step 4: 3
Cut on the line that is 1/8 from the end and keep the ring that you cut off. Make the cut as clean and straight as possible. If you have a belt sander, you can straighten up your cuts.
Step 5: 4
Cut from the lines on the end down to the shoulder line you drew earlier and cut out the area between the cuts so you have two ears. Make sure you cut to just outside the inner surface of the fitting. Drill a 9/64 hole in the middle of the ears.
Step 6: 5
Cut a ring of 1 inch pipe the length of one end of the fitting to the shoulder line you drew. Lay the ring on it’s side and cut a slit down its side.
Step 7: 6
Cut a piece of 1/8 rod the same length as the width of the outside of the fitting and smooth the ends of the rod.
Cut a length of 1/2 sch 20 pipe the length of the bone you want and sand down the outside, the length of the inside on the fitting, so it slides freely into a fitting.
Slide this pipe into the side of the fitting that you cut the ring off of and mark where the end of the fitting is and drill a 1/8 hole through the pipe.
Step 8: 7
Spread the 1 inch ring and slip it onto the side of the fitting without the ears. Leave enough space on the end for the ring you cut off and the 1/8 rod.
Put the ring you cut off the fitting and put the 1/8 inch rod in the hole you drilled in the 1/2 inch pipe. Slide the pipe into the fitting and work the fitting ring into the 1 inch ring.
Glue the 1 inch ring to the fitting and fitting ring.
Take out the rod and remove the pipe. Drill a 1/8 hole in one side of the fitting through the 1 inch ring so that the hole would go through the 1/2 inch pipe(if it were in the fitting). Tap the hole with the 8-32 tap, put the joint back together and insert a 8-32 set screw into the hole you just drilled. The set screw will lock down this side of the joint.
Step 9: 8
On another piece of 1/2 inch pipe cut the length of bone you want, slip it into the ear side of the fitting and mark where the holes are.
Remove the pipe, drill the holes to 9/64 and round the end of the pipe.
Insert the nylon spacer into the pipe on the end you just worked on, slide the pipe into the ears and put in a 6-32 screw and nut. Tighten this screw to lock this side of the joint.
Step 10: 9
Completed joint. In the photo with the two joint fittings, the one on the left is how it should look when its done. The one on the right, the ears are wrong.
Step 11: 10
A completed arm on my massive zombie freak! Just hit the ends with some GreatStuff to build up some bony landmarks, spray glue some muscles made out of plastic drop cloth, cover with a layer or two of plastic drop cloth, hit with a heat gun, paint it up and he’s good to go!