The link below is a very valuable resource for restoration parts and mainsprings you commonly need to fix and restore Pocket Watches.

Parts, (Note the many different watch makers are listed in the left column, click there to see what is available);

http://www.jewelerssupplies.co...Watch_Parts-ss2.html

Mainsprings:

http://www.jewelerssupplies.co...ing-size-charts.html