You can get 3d printed parts in metal using Selective Laser Sintering (SLS). Shapeways or i.Materialise will be able to provide those.
The high end machines (not a cheap extruder) can give you very good tolerances. Especially with photolithography. They can't give you really tight tolearnces, but standard machining tolerances (+/- 0.005") aren't unheard of.
But Andreas is right. Forget about any strength. The parts don't have any. If the part sees any real load, don't even try it.
The prices aren't bad though. I designed a replacement power plug for an Arri 16SB, and had the shell printed for $8.94 in Nylon. It cost me about $12 finished. It's tough, and able to handle the job. But the part doesn't see any load.
And luckily, Super 8 cameras were mostly built with cheap commodity injection molded plastic parts in the 60s and 70s. Replacement parts don't have to meet tight tolerances or high strength requirements; for the most part; just OE tolerances.
So, if you have a good CAD package, and know how to use it, it's certainly possible to build replacement parts for most Super 8 cameras.
Edited by Zac Fettig, 07 June 2013 - 08:33 AM.