The most simple solution would be to install either a Benjamin cap
or a test plug:

http://www.mobilemart.com/product.aspx?sku=11981

http://www.plumbingsupply.com/testing.html (scroll down to see 3
types)

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______________________________
Keep the whole world singing . . . .
DanG (remove the sevens)




"Matt" wrote in message
...
wrote:
Matt wrote:
If the hole is not 60mm, what size other than 60mm would be
about 60mm?

A 2" NPT pipe thread is approximately 60mm in diameter.

See, the NOMINAL diameter of the inside of a 2" iron pipe is
2". The
wall thickness is approximately 3/16" thick. 60mm is
approximately
2-3/8". You do the math.

You say the new plug is plastic?


Yes, and so is the old one.


You won't hurt the cast threads a bit
if with a plastic plug if you happen to cross-thread it. The
plastic
threads will simply strip out.


Right, well, I can't get the new plug to stay in. I get the
threads to barely engage, but the plug pops out when I turn it.
Then I look at the threads and see that they are deformed.
Isn't this explained by rust filling the threads of the drain
hole?


I'll bet if you compare the two plugs closely you will see they
aren't
quite the same...


I don't much want to take the plug out just to check. My
explanation of
the old plug going in easily and the new one going in hard is
that the plastic threads of the old one are deformed (somehow
crushed and/or shaved) so as to conform to the rust-reduced size
of the threads in the drain hole. It seems basically that the
end threads of the old plug are smaller than the other threads,
as if the plug is tapered more. The new plug is not so deformed
and the threads are too big to go in.

I come back to the question of whether there is some size close
to 2 3/8" that isn't 2 3/8". I don't believe anymore that there
is such a thing as a 60mm nominal plug.

In what way(s) do you think the old and new plugs might
differ---I mean how might they have differed when they were both
new?