I need to connect a 1/2 inch pvc threaded male pipe to a threaded female copper shut off valve, but the male threads appear to slightly finer than the female. Is this possible? Will I have to redo the male end to match.

Can you explain further, pvc pipe does not have threads but may have a adapter glued onto the pipe. 8 in. Schedule 40 PVC Male Adapter MPTxS-436-080 at The Home Depot (http://www.homedepot.com/webapp/wcs/stores/servlet/ProductDisplay?productId=203218413&storeId=10051&langId=-1&catalogId=10053&ci_sku=203218413&ci_kw=%7bkeyword%7d&kwd=%7bkeyword%7d&cm_mmc=shopping%2d%5f%2dgoogleads%2d%5f%2dpla%2d%5 f%2d203218413&ci_gpa=pla)

Correct, it has 1/2 inch male adapter glued to end of pipe. Am installing new faucet with 3/8 inch female ends. Decided to include 2 1/2 inch to 3/8 inch shutoff valves with the new install, but the threads appear to be different between the pipe adapters and the shutoff valves.

1/2 IP is the same in copper, PVC, CPVC.

Well I guess the best thing to do is take back the shutoff valves and try a different brand. Thank You

I really can't picture the threads being different, they are not like nuts and bolts that come in different thraeds. have you tried threading them together? Different brands do not use different thraeds. They are all PT (pipe thread)

Might try just buying a pvc male adapter and try screwing it in. If, for some weird reason, it doesn't work, at least you haven't messed up what is already there. If it does work, then you are good to go.

Found the problem. The male adapters were indeed a finer thread (must have really been old). Cut both off and put on new ones and everything is fine. Thank you for the help.