I found this little (well, not so little) gem at a yard sale some 20 years ago. It's home-built, with a fire extinguisher body, a clothes line pulley with Mamod-looking pulley for a belt drive, a piston made from an old bolt, a cut-down CO2 cartridge for a functional whistle, recycled gas taps everywhere, and who knows what else?
I made a frame for it, removed the plastic lawnmower wheels and replaced them with cast iron ones, scrapped the small flat clothes iron that had been used as a heat source, installed an old pressure gauge, and did a thousand things you have not dreamed of.
Believe it or not, it runs smooth as silk in either direction on about 3 lb of air, and was towed all over by my three-year-old grandson in 2004 and beyond as a favourite toy.
If you look closely, you'll see a lubrication reservoir above the cylinder, and a piece of shoelace leading from it that licks the piston with a film of oil. Whoever made this was a mixture of crazy and genius, I think.
I've put quite a bit of time into it and kept it all these years just because it's so strange....  
[ Guests cannot view attachments ]
[ Guests cannot view attachments ]
[ Guests cannot view attachments ]
[ Guests cannot view attachments ]