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mugsie
04-09-2008, 07:09 AM
I just purchased a Lyman 200 SWC mold from Midway. I had to wait several weeks because it was on back order. It arrived yesterday and the top of the mold loks like leopard spots. Circles and rings of what appear to be rust! the mold it date coded 12-07. The spru plate looks like it was a stamping, very rough edges on the lower portion with machined edges on the top, when viewed from the side. In other words, when looking at the thickness of the spru plate, the top half is machined but the bottom portion where it meets the mold looks to be a rough casting. I am very disappointed. Has this ever happened to any of you?

BABore
04-09-2008, 08:07 AM
Sounds like it probably rusted a bit in storage. The sprue plate is normal. You are correct in that it is a stamped part. What you are seeing on the edge (thickness) is call break. The stamping die shears through approximately 1/2 to 2/3rds of the material and the remaining thickness is broken off as the die pushes the blank through the lower portion of the die.

You will need to lap the underside of the plate on a flat surface (glass or granite plate) to ensure it's nice and flat. Once done, stone all of the underside edges to produce a slight taper, then round the corners slightly. This leaves a little draft on the edge as the plate swings acrossed the edge of the block tops. On only the highest dollar molds will you find all of this done for you (usually). Something you need to get used to when getting a new mold.

Always check block fit, wobble when closed, alignment pin mating and release, sprue plate finish, and tightness as soon as you get it scrubbed clean. In the middle of casting or after is not the time to address any problems as your likely to damage the mold or plate.

HORNET
04-09-2008, 12:41 PM
Pretty much standard new mold tuning requirements anymore. Also check the vents to make sure they're clean and not burred shut. I even do all that even on RCBS molds, and especially on used molds.

jrgift
04-09-2008, 05:38 PM
I would order a replacement plate from Lyman any way ,one of the thicker plates that do a better job.