cleaning/dressing old pipe threads

[Gardner]

I have a somewhat grotty old 3/4 threaded hub on a galvanized steel fitting and I need to thread a new 3/4 brass fitting into it. The old threads are not particularly nice, but they are likely serviceable. Is there a standard procedure for cleaning and dressing an old rusty, putty-encrusted fitting to take a new fitting and make a good seal?

I was thinking of getting a 3/4 black pipe nipple, cutting a slot across the threads (like on a self tapping screw) with a grinder and using this to run into the old hub to clean up the rust and crust. Kind of a home made chasing tap. Is there a better way?

 

[NHmaster]

Lotta work when you could just bust out the wire brush. If the threads are bad you need a 3/4 npt die to chase them.

 

[Sponsor]

 

[Gary Swart]

You might find a set of pipe dies at a tool rental store. Shouldn't cost too much for half a day. If you were in Yakima, I'd loan you a 3/4" die.

 

[Nate R]

You might find a set of pipe dies at a tool rental store. Shouldn't cost too much for half a day. If you were in Yakima, I'd loan you a 3/4" die.

Doesn't he need a 3/4" tap?

 

[NHmaster]

I have a somewhat grotty old 3/4 threaded hub on a galvanized steel fitting and I need to thread a new 3/4 brass fitting into it.


Yep.

The disadvantage of speed reading

 

[Gardner]

Thanks all. I'm sure the hub won't be so bad I need to run a real tap into it. I expect I can get by with a wire brush. This is a cottage/camp project and I am trying to plan ahead for what I may need when I get there and start working on it, so that's what got me going on pre-fabbing a low budget tool, just in case.

Besides the bogus threaded 3/4 fitting on my pump to fix, I also have a couple of burst copper lines to take care of, as well as correcting the pitch of those lines and adding a drain to avoid water staying in the lines next year.