4 cavity Lyman mold, sprueplate hold down screw adjustment?

[stubbicatt]

Guys, on the Lyman 4 cavity mould block half, at the opposite corner from the sprue plate hinge screw, there is another screw for holding the sprue plate snugly against the top of the mould. Mine requires me to snug it each time I close the blocks, and close the sprue plate. Is there a good way to keep it from coming loose?

Thanks in advance.

[Catshooter]

Are you saying that the screw comes loose each time you cycle the mould?

Some blue Loktite? Or, you could install a set screw in the side that would bear against the screw.

Welcome to the forum.


Cat

[stubbicatt]

Yes, Catshooter. It comes loose, if not every time, maybe every other time. It is ok, I guess, I close the sprueplate, and just a little snugging with a screwdriver. As I think on it, I wonder if maybe this is a symptom of a sprue plate that has warped or something. I guess I'll take it apart and examine it with a straight edge, and using a stone or some valve grinding paste flatten it out again, if possible, if not, replace it.

[CJR]

I had the same problem with all my Lyman moulds. The sprue plate hold-down bolt kept loosening up no matter how many times I tightened the locking set-screw for the hold-down bolt. On inspection, I found the set-screw threads were not completely tapped and acting like a tapered thread. So everytime I tightened the set-screw it would only tightned so far into the tapered thread and lock to leave the hold-down bolt slightly loose, Solution? Finish threading the set-screw threads and problem vanished. Hope this helps.

Best regards,

CJR

[bhn22]

Guys, on the Lyman 4 cavity mould block half, at the opposite corner from the sprue plate hinge screw, there is another screw for holding the sprue plate snugly against the top of the mould. Mine requires me to snug it each time I close the blocks, and close the sprue plate. Is there a good way to keep it from coming loose?

Thanks in advance.

You could remove the screw and deliberately roll over perhaps one thread about halfway up the threads. You could lightly roll the edge over with a small punch and hammer, just enough to make the screw lock into place where you want. This way you only modify the cheap part.

Loctites mortal enemy is heat, so that wouldn't help at all.

[fecmech]

What may help is remove the set screw and drop a piece of lead shot into the hole and then tighten the set screw. This will give more bearing area on the spru plate screw.

[bhn22]

I believe he's asking about the screw that does not serve as a pivot point for the sprue plate.

[stubbicatt]

Yes. The screw opposite the pivot is the one at issue.

Thanks.

[gwpercle]

I don't know if this will work on a Lyman mould, but on two Lee moulds, a pivot screw kept loosening, one suggestion was to take a thin tuft/strand of 0000 steel wool , push it down into the hole , replace the screw, and tighten. I was skeptical of this easy fix......but I had steel wool on the bench and gave it a try. It works, both moulds have gone through several casting sessions and remained tight. I was going to remove one, but it was still nice and snug, so I left it alone. I'm not sure how this works but it does, it's cheap , easy to do and can be reversed.

Gary

[bhn22]

an excellent suggestion!

[stubbicatt]

I'll try it. I still think perhaps I have a warpage issue.

Got a few pounds of lino to sweeten up my alloys a little bit, which may allow me to cast at a lower temperature next time around.

[casterofboolits]

I drilled and tapped several of my four cavity Lyman molds to be able to adjust the tension on the rear of the sprue plate. Same size as the front right set screw. 6-32 ? Sorry, it's been awhile.

[Harles Dawson]

I had the same problem. I used red loc tite. No more problems. Harles