Sprue release problems

[Lizard333]

I have a 2 cavity Lyman mold that will not drop the cut sprue. I have tried three different types of sprue lubes, and no matter what temp I run the mold, they will not release. I probly have 15 different molds and I've never had this problem. I have tried cold, hot, way to hot, nothing. The type if lead doesn't matter as I've tried pure to Lino.

[Doc_Stihl]

I had a sprue plate that held the cut sprue a while back. I had to look under magnification to find the bur. Took the burr off with a file best I could and then I took #0000 steel wool to the opening on both sides.

I've also had trouble with a sprue plate being warped and not so much cutting as shearing off the sprue at a funny angle and it would hold a lead bump on the bottom of the sprue that made releasing hard.

[billyb]

I use a counter sink to clean up the bottom of the fill hole. Try not to overly enlarge the hole.

[Pepe Ray]

When cleaning up the taper of the spru with a countersink be sure to
NOT do it from the bottom.

[Charlie Two Tracks]

Got a LEE hardness tester? You can use the microscope to get a real good look at it. I have a fly tying florescent magnifying lamp on my table and that works good for seeing very small problems.

[runfiverun]

lizard.
I have a sticky called something that may help.
on the last page.
there is a link to ben fixing this issue on one of his molds.

[blaser.306]

I had a Lyman mould that had a sprue plate that was not counter sunk all the way dow! It actualy left a small "pipe" of alloy in the plate attached to the beveled sprue that you normally see.

[Alan in Vermont]

I had a Lyman mould that had a sprue plate that was not counter sunk all the way down! It actualy left a small "pipe" of alloy in the plate attached to the beveled sprue that you normally see.

+1 on that issue. I ran a countersink in to deepen the existing c'sunk bevel until there was a knife edge on the hole, too k care of the issue very nicely.

[Gtek]

If you are going to tap with countersink. Put on drill press or on mill table, center over T-slot, use tool to center, lock plate down well. Slow turn, plates appear to be a little past mild and it will chatter and go fugly fast. Gtek

[josper]

I use a counter sink to clean up the bottom of the fill hole. Try not to overly enlarge the hole. +1 I was having a problem with the sprews hanging up to a point It was a major PITA. I used the countersink just to clean it up and wa la no more problem.

[Down South]

Looks like the question has been answered well several times. I've had to "Clean up" a couple sprue plates in times past for the same reason.

[Lizard333]

Looks like I have a few options to try. I'm going to give them a go.

[.22-10-45]

I made a fixture for mounting plate in lathe..single point tool does nice job of re-cutting sprue c'sink.

[.22-10-45]

I made a fixture for mounting plate in lathe. Single point tool does nice job of cleaning up c'sink.