Next we drill a 1/4" hole into the 90 degree tab at both ends of the shoulders. You will need to make six 1/4" hinge pins out of solid steel rod for the arms of our whiner. The upper arms will be 10 1/2" long, made out of 3/4" x 3/4" angle aluminum as will the lower arms cut to 11". I know there isn't much difference between the two arm sections, but the skeleton seems to look a little more realistic with this minor difference in length. Between each hinge point of the arms I placed a short section of 3/8" rubber air line as shown here. This will keep the aluminum from touching each other during operation and reducing possible joint wear dramatically. At the ends of the hinge pins I drill a small hole and insert a short section of heavy wire that I simply bend over. At the connection for the wrist I place a flat washer between the mount and angle to reduce friction as I will be needing to house this mount plate and connection inside the wrist of my big baby, so this needs to be a compact joint. The mount to the chair is merely a short section of the same angle aluminum as the arms and is screwed down using two 3/4" x #8 pan head screws. This is 4" on center to the hinge pin from the front of the arm rest, centered.  In this shot you can see how the skeleton looks now fully bolted down. And luckily the computer draft dimensions work out ideally once I put him through his cycle. Success! The rest will be just details.

   And let's get started on them now. It's time to deal with his neck to make it more realistic. If you look at anyone's neck where it meets the base of the skull and the shoulders you can see that it is slightly forward of centered. So to make our guy a little less rigid looking we will need to make a couple of cuts to the spine just above the shoulders. Cut out about 3/4" from the lower front cut as shown here and bend the neck forward to close the gap. Now remove about 1/2" from the a cut just above that on the back side. You may have to play with this a little with your angle grinder to get it just right as I did, but the idea is to tilt the neck slight forward as well as moving it's center to the body forward slightly. This will also give enough clearance for the head not to actually touch the seat back when it fully resets. Once you get your angle just right, Use a strap of metal on each side of the neck and screw some #8 pan head screws into each of the three sections to solidly brace it's position. I just used a couple of mending plates that were 2" long each and joined them in the middle, but you could do the same thing with a single piece of steel strapping.  This turned out to be very solid, so there will be no worry of our flailer's head flying off.

   In keeping with the logic of making the drill in the chest of our doomed soul quickly replaceable, I shortened the power cord it came with to just 3" long and then mounted the female 3-outlet end of an extension cord solidly to the spine just above the bottom of the ribcage with heavy zip ties, then I zip tied the power plug of the drill to the outlet. This will keep this connection secure during its cycle but will make it super easy to make the replacement. If you shorten the cord now on your back up drill and fit it with the same plug end as shown on the first one here, you will be ready at a moment's notice to make the swap. And our drill may well last for years of use with this first unit, but not preparing now may end up with an ugly situation in the middle of a huge turnout to your haunt or at the start of halloween night at some point.

   Once we have our guy basically strapped in we need to turn to making sure the air cylinder connections are all in place. One thing that must be done is attaching some return springs to the leg so the feet stomp down very quickly. Since we are using the cylinder to lift them up, we would be left with just gravity for this action and that's not quite as quick as I think would look right. The springs you see here are readily available from hardware stores. You will need to cut one of the looped ends off for the attachment system I have decided to use. Directly forward of the primary mounts on the seat, drill a 1/4" hole through the side of each leg and insert a 1/4" x 1 1/2" bolt using a flat washer through the top of the spring. Make sure you use a lock nut on the other side. Then at the bottom, side a 2" mending plate or similar under the bottom coil of the trimmed end of the spring and then screw the plate down tight to the seat, pinching the spring in place. You will want your spring length to have some tension on it even when the dummy's feet are touching the pedestal. Once you add boots or shoes to the feet it will lift them up further adding a slight amount of additional tension, giving your stomper more animation.  For the rear connection of the leg assembly to the air cylinder you will connect the cylinder to the connecting pin and drill for the safety wire through the nut and the rod as shown earlier in our how to. When I went to install this one, I found that I needed to send the air into the cylinder at the top, so I had to drill another hole in the seat to allow for room for the air line to pass through next to the 1 1/16" hole needed for the top of the cylinder .  The height of the air cylinder will be set so that your total used throw is no more than about 1 5 /8" to 1 7/8" depending on your tastes.  For the mount that will be centered on the back of the seat box below I made a clevis from a section of tube steel similar to the one shown here on the left. This particular double clevis was made for the connection of the torso air cylinder and it's return spring, but if you can imagine cutting this one in half and drilling two mounting holes in the bottom, y0u have what the clevis looked like for this leg assembly. I used 5 /16" steel rod for my connecting pins since this worked with my particular air ram. You can see it hooked up in the photo on the right. Once again we will be using two rubber washers under this clevis where it meets the wood back as we used on the primary hinge to the seat above. This will take some of the concussion off of the bolts and the wood holes they are resting in.