Tough technical questions

"Nomen Nescio" > wrote in message
...
> 1. The application is to install a rotary shaft oil seal in an aluminum
> housing. The configuration of the seal is with a rubber coated outside
> diameter. The fit in the bored housing is a light push fit. I suspect
the
> seal will work loose on its own during service. What is the best way to
> install this seal? Options I've considered include replacing this seal
> constructed with a metal o.d., but this is not normally recommended due to
> the high coefficient of expansion. A more promising solution is to "glue"
> the seal in with Loctite 495, cyanoacrylate adhesive. Will that work?
>

Loctite 609 would be a better choice, IMO. 495 is just common super glue,
and would probably not be suitable for use on oil seals.

> 2. The problem is installing a chain sprocket onto a keyed tapered shaft
> which is then secured with a retaining nut. What is the best practice:
> Install on clean and dry taper, install on greased taper, or apply a high
> strength Loctite 272 to the taper before assembly? The idea is to make a
> good assembly but be able to disassemble with no more than a puller
without
> heat. Am I correct in assuming that the key is designed for indexing but
> the torque is taken up by the taper?

Yes

If the taper is greased, removal is
> easy, but the torque might be passed on to the key and cause localized
> stress and failure. Clean and dry I think is the standard way of
assembly,
> but Loctite application may be in common practice too.
>

I agree with the "clean and dry". If you are worried about it loosening on
the shaft, you could always heat the sprocket in a pan of water before assy,
then immediately torque the nut down. A little 242 on the threads would keep
the nut from loosening.
H