[TheForge] OT - Grease/oil seals for a gear box

[Peter Fels & Phoebe Palmer]

Bruce..there should be a huge selection of standard oil/grease seals 
available if your shafting is standard sizes.
Alternately, you could take some teflon packing cord and fake up a 
compression seal that ought to do fine. A home made O ring seal isn't 
all that hard but will have a shorter life, depending on the finish of 
the shaft.

Bruce Freeman wrote:
> I'm constructing a simple gearbox for a mechanism I'm playing with.
> The gearbox itself is of no importance except as to provide power to
> the mechanism, and the nature of the gearbox is such that I cannot
> simply buy a commercial unit.
> 
> Perhaps naively, I simply mounted sealed ball bearings into
> appropriate recesses in the housingn, counting on the small clearance
> between bearings, shafts and housing to  seal against oil leakage.  No
> go.  The oil leaks right out pretty quickly.  Grease works better, but
> also leaks.  Loss of grease is not a problem - the potential for
> contamination of the driven device is the problem.
> 
> Next I tried sealing between bearings and shafts or housing with a
> medium-strength "lock-tight" product.  No go.  Oil leaks right out
> when gearbox is run.
> 
> I could go to a product like RTV rubber, but I'd probably never be
> able to change out the bearings again if I did that.  Still I may
> consider it.
> 
> I'm looking for other ideas.  I'd prefer not to remanufacture the
> housings, but  could do that if necessary.  For example, I'd have to
> do something like that if I went to O-ring seals.  However, I'm not
> convinced O-rings would do a better job, so am not ready to take that
> particular step.
> 
> How is this done in commercial mechanisms?
> 
> Any suggestions would be appreciated.
>