I'm working on a project to build a little mechanism. It's something that I want to hand out at seminars, so I want to keep the cost down. But it needs to be able to hold together while one person uses it intermittently, possibly for years. The current design concept involves a sheet-metal base (with a stiffener in the right place), and a 4mm shaft that supports the working elements.
My specific frustration of the moment is bearings for the shaft. I'd really like something that I could plug into holes in the sheet metal that would support the shaft.
But pricing is nuts. I can go into a hobby shop and buy a package with half a dozen ball bearing assemblies in it for a toy helicopter, and pay $9.99. Or I can go to McMaster and get an instrumentation-quality bearing in the size (4mm ID) I need and pay $12 or so _per bearing_. I'm not even sure if ball bearings are the right choice given the fact I'm putting them into sheet -- a nylon or teflon bushing may be just right if the friction is reasonably low.
I've spent way too much time already looking around on the web. The only thing that I've found that's close is some panel bushings from McMaster -- I may end up with these, at least in the short term, or with hand-machined pieces of teflon just to prove the concept.
Where can I find cheap bearings? I don't need aerospace quality, I don't need copy machine quality. All I need is something that'll reduce friction more than stuffing a steel shaft through an aluminum hole, and that will stand up to light use for an indefinite period of time.
I'm assuming I need to look for something imported (I'm in the USA), and if this idea flies I'll be buying parts several dozen at a time.
Does anyone have any names of companies or distributors that may have these?