Are you in a book club/group?
I just joined one. We're all meeting tonight for the first time to get to know eachother and come up with a reading list.
I just came across this funny article on book groups:
2009 gate valve infomation
Gate valve normally have flanged ends which are drilled according to pipeline compatible flange dimensional standards. Gate valve is typically constructed from cast iron, ductile iron, cast carbon steel, gun metal, stainless steel, alloy steels, and forged steels.