Here's a newbie question: When using a Lyman single cavity mould for long runs the sprue plate will not stay tight. The problem appears to be the spring washer next to the plate under the screw  has collapsed. Is there a simple fix for this problem? Thanks for the help. 

J.G.Terry,

George is correct, Lyman moulds do have a great tendency for the sprue plate to become loose, due as he says, to the screw backing out. If you think the spring washer is damaged take the screw out, lift of the washer. Examine it to see if there is 'spring' left in the material. If not your local hardware store may be able to help you out with a replacement for just a few Cents. Alternatively get in touch with Lyman and tell them, they're likely to send you a replacement or two FOC. Good luck.

Harry

I toss the spring washers. PITA.

      Joe.

Belleville washers.   Much better'n plain lock washers.

Thanks for all the help. The first step was to replace the spring washer with an ordinary split lock washer from the local Ace Hardware. There was a significant improvement but was, as suggested, necessary to keep tools handy.