# What makes a good sturdy arm? How to Drill Aluminum stock?



## gargoyle7 (Sep 21, 2013)

Hey there all!

I am new to props, but having a blast help my cousin build some stuff, we have a flying crank ghost, and soon to be a cauldron creep

My question - I struggle with finding good aluminum stock 'arms' for, say, the flying crank motor, what we have now is very 'bendy' and the weight of the ghost almost cripples it.

1. what makes the best material for arms?

2. how is the easiest way to drill it? I have no drill press.

3. I worry about getting working drive arms for the 
'creep', whats the best advice for freely rotating joints? For instance, the drive arms with this reindeer motor:






he uses carter pins, whats the mechanism here?

Thanks!

Lee in NC


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## Hippofeet (Nov 26, 2012)

The drive is a wiper motor inside the cauldron. The arms can be anything, they will move with the motor, not push the stick.

Aluminum? 3/4 inch with a 1/8th (.125) wall. Steel flat, 1/8th (depending on distance, I mean, its gonna bend over feet, but not inches) steel square tube, I like .08ish or even .06ish.


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## Kelly_A (Sep 24, 2013)

Drilling aluminum stock is as easy as marking the location of the hole, using a steel nail to "center punch" the mark for a starting spot, placing the stock on scrap 2x4 and drilling with a small bit right through the stock into the 2x4. 
Increase the bit size a couple of times until you have the diameter hole you need. 

I use exactly the stock Hippofeet mentioned 3/4" wide by 1/8" thick. Lowes sells lengths for less than seven bucks.


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## gargoyle7 (Sep 21, 2013)

thanks guys, helped a lot


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## Doc Doom (Aug 28, 2008)

I used 3/4" x 3/4" x 1/8" thick aluminum "L" stock. Doesn't flex at all.


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## gargoyle7 (Sep 21, 2013)

Thanks Doc

GOOD quality U bolts (or other apparatus for attaching arms to a motor shaft), where are they in Lowes? Maybe under another name?


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## gargoyle7 (Sep 21, 2013)

PS, Oh and any good detailed descriptions on a freely rotating mach at end of an arm for a flying crank ghost, mine is just shotty, it works but crappily, basically various washers on a bolt, bolt tightened two nuts, comes loose easily

Thank you guys


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## gargoyle7 (Sep 21, 2013)

*mech* not moch


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## scarybill (Oct 7, 2012)

Gargoyle, get some self locking nuts(the nylon type) and use these. they do not come loose and you can "set" the amount of clearance you want.


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## Hippofeet (Nov 26, 2012)

For a flying ghost, or even some heavy (35+ pounds) animatronics on a flying ghost setup, I use basically a tube in a tube. The larger square tube mounts to a plate that mounts to the (insert what you are mounting it to).

Another tube, you can look up telescoping tubing, go like 10 thou smaller on the inside tube, at least, is the part the motor and drive pulley mount to. So the motor drives the drive pulley via a very short belt, this way you can play with pulleys and control speed, or you can play with voltage control and lose torque. Your choice.

I will just post a vid, with a drawing on a whiteboard, it's too hard to explain, and I don't have one pre-built right now.


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## Hippofeet (Nov 26, 2012)

Vid. At some point, someone who doesn't even work here walked up and acted like I must be utterly insane, and just talking into space, lol. Weirdo.

"Who are you talking to?"

duh.

Anyway...


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## Hippofeet (Nov 26, 2012)

Hahaha

My videos suck!

I just watched it. I really am much more sure of what I'm doing than I appear to be.


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## gargoyle7 (Sep 21, 2013)

hehe Hippo, I appreciate the effort! But I vaguely know what you are getting at, but think I get the picture. Thing is I am not a welder at all. Yet! Thanks man.


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