On 27 Dec 2005 09:46:36 -0800, "mlcorson"
wrote:

I really need some help in finding a place to start to get self
educated on bearings, shafts, and tubes. I've been welding metal
together for the last year, mostly stainless that I get from the junk
yard. I've boldly called it sculpture, but only when I was lucky enough
to find a piece of scrap or cutout that by coincidence looked good when
welded together. I am now planning on a series of kinetic or moving
sculptures. What I am looking to do (at least initially) is a counter
balanced piece that is long with a pivot point near or at the center of
gravity, pivoting on a tube, bearing and shaft type arrangement. Simple
tube and shaft arrangements (sans bearings) will not really work
because of the friction involved. I have a great resource for scrap
material, so I wouldn't want to get into purchasing a lot of virgin
materials. However, bearings and similar items at the junk yard are
just sometimes not worth the time and effort to re-engineer for a new
purpose. Also, found items seldom match up perfectly, all complicated
by the fact exact measurements are seldom known. How would I go about
this? Find shafts and tubes that are in what proportion to allow a
bearing to fit? Start with a bearing? Then match tube and shaft? I need
a "Bearings for Dummies" book or similar resource(s). Any help here
will be greatly appreciated. BTW, I have a mini mill, and a 7x12 lathe.
I'm a total novice operating those however. Thanks.
-Mike (in St. Louis)

Not knowing the sizes or weights of your projects it is hard to advise
you on the type of bearings you may need. Go to
http://www.ntnamerica.com/

then click on "Products" in the upper right hand side of the page.
Toward the bottom of the page click on "General Bearing Knowledge
Base". There you will find information on all types of bearings
including mounted units (which don't require machining to mount). If
your loads and speeds are moderate (60 RPM for example) you might try
UHMW or Nylon - both of which can be machined and which are available
in pillow block style. Once you have a better idea of available styles
and capabilities come back with any questions you might have. Good
luck.