The Home Machinist!

Dumb question:

Is it possible for a garage machinist with a Chinese mini-mill to machine mating surfaces precisely enough to achieve an oil-leak-proof joint without a gasket or seal of any type? How about using thick oil?

Jim

short answer...no
even if you could get the precision needed (unlikely) you most likely couldn't get the surface finish needed . Even the crankcase of my airplane used a silk thread to provide a "crush gasket" to seal

With machining only, I doubt it. Add a reasonable lapping plate, plus skill, and I think it can be done.
Round parts will need honing and lapping.

Any irregular surfaces, not a chance. (Without LOTS of hand work.)

Dave J.

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Every day I ask myself, "What's the most fun thing to do today."
9x48 BP clone, 12x36 lathe, TIG, MIG, Gas, 3 in 1 sheetmetal.

okay.....how about a thin layer of Vaseline squeezed when the joint is fastened with cap screws? the walls will be 31/32" tick, so that's a nice, wide joint. I really don't want to make grooves for o-rings or deal with gaskets. There will be no pressure - it's a rotary table - it's just for simple lubrication. Maybe a 5" rotary table does not even need constant lubrication?

I wonder if even gauge blocks wrung together would be "oil tight".
...lew...

Use a thin film of orange silicone and install, that is what I use and works fine.

Richard W.

I've used Loctite 5452 for low pressure to high pressure hydraulics, for metal to metal fits. It'll even seal JIC fittings that have taken some hits, when you don't have the time, or the stuff to fix things right.

Bill

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Today's solutions are tomorrow's problems.

I don't see why not. I have taken apart hydraulic pumps that had no seals execpt where the shaft enters. Just ground surfaces and bolted together.

Richard W.

I'm not sure I'd want to use something that is too thick in consistency. The reason is that I wouldn't want to interfere with the alignment of the base parts. I'm making this table so I can then make a high-precision worm gear for a go-to telescope. Any irregularities in the base or other components of the table would compromise the accuracy of the gear, which, in turn, would reveal itself in the inconsistency of accurately pointing to objects in the sky. Therefore, something that had a lighter consistency, such as Vaseline, would certainly squeeze out a lot better and only remain wherever there are voids. Tell me if my logic is messed up.

Vaseline is nothing but cosmoline with the sulphur removed. Its not intended for sealing anything. Silicone will squish out very thin as it would only remain in the low spots of the surface finish. I have peeled it off parts where it was so thin you could almost see through it. If that isn't good enough then cut grooves for an o-ring. Just remember if the groove isn't wide enough to allow the o-ring to compress with out filling up the groove completely, then your condition would be worse and warped parts may be the result.

Richard W.

???

Sealing tight metal to metal joints >>>> Loctite 574 or 518

Joe B