Yeah, I find it a little strange that the hole has no threads??? I wonder if there is a coupling on the market that is compression fit, I would say try your luck with a plumbing contractor instead. This may be another far fetched idea, but if ya got a pulp mill close by, you'd be surprised what kind of fancy fittings you'd find there.
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Pi$$ on the ceiling... Any ******* can Pi$$ on the floor.
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Pi$$ on the ceiling... Any ******* can Pi$$ on the floor.