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flhroy
01-30-2012, 07:37 PM
I picked up a used 4 cavity 358429 lyman mould today. It looks to be in great shape BUT I do have a question. How much of a gap should there be when lifting up on the sprue plate? When I first got it it had 1/16 + inch gap on it. I tightened the screw and can just about eliminate any gap at all. Is there a technique to adjusting the sprue plate?

Thanks

Grandpas50AE
01-30-2012, 07:45 PM
You want as little a gap as possible, but the sprue plate should move freely.I would leave a few thousandths so that when the sprue plate and mold expands from heat the sprue plate will move freely without any excess gap.

stubshaft
01-30-2012, 08:43 PM
Does it have a wave or lock washer below the screw head but above the plate? There shold be only a few thousandths of clearance. When you tightened the sprue did you loosen the retaining screw on the side of the block?

beagle
02-01-2012, 02:26 PM
Good point. I use both a wave or bellville washer concave side down topped by a lock washer. The bellville washer provides a flat, pivoting point around the screw on the sprue plate and the lock washer provides spring tension on the bellville to hold it flat. That way, the sprue plate has constant, spring loaded pressure against it at all times and the give in the lock washer allows it to pivot smoothly./beagle


Does it have a wave or lock washer below the screw head but above the plate? There shold be only a few thousandths of clearance. When you tightened the sprue did you loosen the retaining screw on the side of the block?

runfiverun
02-01-2012, 09:40 PM
i watch from the side and tighten just enough to put some friction pressure on top of the mold when opening and closing it.
making sure it is level [the sprue plate]
you'll know if it's wrong. too tight and you'll get flashing under the back hole[s] too loose and you can get flashing on the front one[s].
sometimes this allows the plate to swing freely on it's own weight sometimes not.