[AT] pipe threads

[John Hall]

I think NPTF is also known as dryseal. We do a lot of hydraulic cylinder 
heads and have seen both used although our customer normally wants NPTF. The 
rest of our customers (none of which deal in hydraulics) always use NPT. 
Supposedly you can interchange one for the other but I don't know which one 
you can.

A good website to help with thread questions is www.marylandmetrics.com but 
I think their USA thread stuff is incomplete. Still a great resource if you 
ever start dealing with "foreign" thread forms.

John Hall