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Bored At Work - The Latest Stuff

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Double-acting compressed air engine

Materials:
Plastic sheet, balloon skin (seals), thick paperclips (adjustable crank), normal paperclips, pen tip and silicone tube (adjustable piston), clicky pen mechanism (low friction valve), machine oil (cheating, but might substutute with bathroom soap or butter from the fridge sometime anyway)

Does it work:
It isn't finished by a fair way, so not yet. I've got a good looking valve low friction slide valve (2-way), and a decent looking piston tube with an inlet port at either end. It needs another valve for exhaust air from somewhere, then a tonne of plumbing. I found some thin silicone tube in the carpark (presumably from a car windscreen washer system) though so that's sorted. The piston seems to turn air pressure into force, which is encouraging.

Hardest bits:
Sticking the seals onto the valve and piston.

How long to make:
So far a couple of weeks, but with less free time than before.

Special bits
The folds in the crank can be straightened or bent further to adjust the stroke of the engine. I'll be able to tune it to exactly how big the piston allows in the end. Piston ring is adjustable too, like in the stirling engine above.
 
Water pump

Materials:
Pen tube, rubber pen grip shroud (piston seal), silicon tupe (piston ring), thick rubber band (one way valves), lots of aquarium glue, paperclips (handle and gudgeon pin)

Does it work:
Yeah! It works pretty well. It can pump water pretty quickly from one cup to another. It does leak back a little, and you sometimes get a bit of water leaking out the top of the pump tube past the piston, but it works!

Hardest bits:
The seal is a lot tighter on this piston than the others since it's hand cranked. There's no lack of power to worry about. Problem is making it all strong enough to cope, and I've bent several gudgeon pins testing it. There's a logistical problem making this too. Aquarium glue stinks, and you have to do all the glueing in small stages or the smell becomes suspiscous!

How long to make:
A couple of weeks.

Special bits
The one way valves are simple and remarkably effective. Just a strip of thick rubber band covering a hole. When there's water pressure one side, it lifts. Pressure on the other side makes it seal. Also, the piston can be removed from the cylinder to maintain the fit of the two piston rings.
 
Electric motor

Materials:
None yet. I'm sure it'll use paperclips though. And magnets. And batteries. Not sure where to get the magnets yet. Maybe there's some in the door mechanisms. I know there's a couple in the crappy penknife tool but I don't think they're big enough.

Does it work:
Not yet, it's just an idea at the moment. Tricky bit is finding appropriate magnets.

Hardest bits:
Dunno yet. Probably be along the lines of setting the distance between the armature and the magnets.

How long to make:
Not long so far...

Special bits
None yet.
 

The early stuff | The good stuff | The latest stuff




Underwood's Axioms 1b: Things take longer (ns)