The room we convert for the annual Halloween party has a piano. Last year one of the props I wanted to make was a pair of skeleton arms that would hang down from the piano and twitch, but I didn't quite have time. Now I am trying to build them for under $20 for the Unpleasant Street $20 Prop Challenge. I got the idea for re-enforcing and painting a blucky from halloweenqueen, Thanks!
| ITEM | COST | QUANTITY USED |
| Blucky Arms | $3.00 | 1 pair |
| Opps gray | $1.00 | trace |
| Opps brown | prorated with gray opps | trace |
| White paint | prorated with gray oops | trace |
| latex painters chaulk | prorated with gray oops | trace |
| Red spray paint | $1.98 | 1 |
| Motor (DCM-220 from allelectronics) | $2.50 | 1 |
| 1 9volt battery | $0.99 | 1 |
| 1 9volt battery clip | $0.33 | 1 |
| 1/2" dowel (3') | $1.39 | 1 |
| 1/4" nuts | $0.98 | 4 |
| eyebolts | $0.98 | 6 |
| 2 8" 1/4 eyebolts | $1.00 | 2 |
| 3" #10-24 screw/nuts | $0.98 | 1 |
| 1/8"x1" fender washers | $0.98 | 1 |
| 1" #10-24 screws/nuts | $0.98 | 2 screws, 8 nuts |
| #210 eyebolts | $0.98 | 2 |
| scrap wood | 0 | 1 thin ply for base, old fence picket for the rest. |
| old shirt | 0 | 1 |
| old ball point pens | 0 | 2 |
| total | 18.07 |
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Here is the initial purchase, and the old blucky arms . |
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Here is a hand before building. I cut the fingers off just inside the last knuckle, and the tip off the the thing that inserts into the wrist bone. An old fountain pen sleeve, cut in half, makes a good bushing for a 1/4 bolt. I drilled a 1/4 hole lengthwise through the scrape wood, and over bored it slightly on one end so the pen sleeve could be glued in. |
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Here the wood insert is assembled and pushed into the hand. An eye bolt is mounted on the eye-bolt with 2 nuts, and the excess drimeled off. I mounted the eye bolt so that when the arms are hanging down, the eyebolt is horizontal. The was cut so that the eye bolt on the end will barely protrude from the wrist bone when it is mounted. Slide the wrist bone over the dowel. Then I bent the slightly so the arms would not hang straight down, but would lean out a little. I thought this looked more realistic. |
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The last dowel is cut so the end of the bone will butt against the dowel when slide over the dowel. The bone is then secured to the end of the dowel with a screw. It is easy to open a screw eye slightly with needle nose pliers so you can hook 2 screw eyes together at the wrist - arm bone joint. |
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When I finished I saw I had not provided a way to attach the hand, so I redesigned the wood insert to have some extra sticking out so I could screw it to a base board. |
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Here is the first arm hanging and waiting for a motor. You have to use your imagination to picture it twitching, trying to escape. |
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Both hands are done. Now it is time to corpsify the arms while I wait for the motor to arrive. I selected a small DC motor with a gear box that results in 70rpm at 6 VDC. I only needs to tweak a cam or arm attached to the eyebolts a little, I hope it is up to the task! |
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Painted the arms opps paint brown left over from Halloween 2005, followed be dry brushing opps gray I bought for this project, followed by a light white dry brushing from some white paint I found lying around. Now I think some ragged sleeves and the arms will be done except for the motor. |
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Well, this is not exactly what I had in mind. This looks very, well, fake! Time for the sleeves to spend a few days in the ground by my favorite leaky sprinkler, then definitely more shredding. |
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The motor finally arrived, now I just have to figure out how to hook all of this together. |
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Since the motor didn't come with a shaft I have to make one. Drill the rivet out of the final gear VERY CAREFULLY. I held the motor flat on the work bench and used the bubble level on my drill to help drill STRAIGHT into the rivet. Start with a small bit and work your way up gradually. |
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Used an old #8 shaft lying around (I'll get a price later). Had to drill out the gear slightly with 11/64' drill bit, the tap the shaft in with the gear lying flat on the work bench. Spin the shaft and check if the gear wobbles, need to adjust the gear if it does. Also had to drill out the motor mount so the new shaft fit (11/64' followed bydremel tool). Fortunately the gears still engaged properly when I was finished. |
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Used a piece of scrap wood to support the shaft. Drill the hole by scraping a pencil over the end of the bolt. Then with the motor mount and wood piece lying flat on the bench, push the shaft through the mount and twist it against the wood. This will give you a mark where you need to drill. A couple of 1" dry wall screws up through the base board into the wood piece secures it in place, the motor mount can be attached later. |
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With the hands, motor and shaft support block positioned (not attached), figure out how to cut a piece of 1/2" dowel for a rocker arm, remembering to allow for the eye bolt. Once its cut, clamp it down and dremel out enough for the head of the eyebolt to slide in snuggly. |
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Here are the pieces to complete a rocker arm. An old IC ball point fit around a #10 bolt just right (thats the white piece, cut from an old BIC pen). Use on nut to clamp the screw to the eye bolt. Use the other 2 nuts to lock the BIC pen piece in place as a bearing (the pen piece will be able to spin, but move only a little). |
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Put everything back in place and slip the fender washer over the shaft. Trace a shape for the cam, then cut it out with the Dremel. |
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Here is everything put together. Notice the shaft is held in the wood block by a couple of #10 nuts. A couple of the 1" #10 screw/nuts are used to secure the motor mount. The rocker arms (dowels) are glued to the eye bolts with a good wood glue. Finally, I bent the arm on the motor solenoid so the motor is always engaged. |
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Here is the final picture. I finally decided on bright red sleeves to offset arms, and used red spray paint. |
