Sprue plate lock bolt loosening easy fix (30 seconds no modifications)

[Andy]

A friend showed me an easy no-modification method to keep the sprue plate from loosening on a lyman mold. This probably applies to any mold that has a lock nut, where the lock nut (allen set screw) doesn't apply the right force to actually keep the sprue plate screw from turning occasionally. This has worked for me personally on two lyman molds and an ideal single cavity.

All you do is remove the sprue plate lock set screw (with sprue plate screw still in and threads visible) and insert one piece of #7 or 8 lead shot in the hole, then re-insert the set screw. The lead bites the threads and gives enough friction to make the system work for hundreds of casts without adjustment. Last week I cast 500 bullets non-stop in a mold that previously needed tightening every 20-30 bullets.

If you find that the set screw will not fit in after inserting the shot, either go to a smaller size of shot or flatten the shot and align it flat with tweezers in the hole to give the set screw room to thread in.

I wanted to pass on this idea as it is dirt simple, works great and doesn't make you alter your mold like filing a flat on the sprue plate screw.

[454PB]

The same method was used to secure reloading die lock rings in the old days (maybe it still is).

[Calamity Jake]

As that piece of shot tends to soften or melt if you get the mild to hot.
I use my dremmel tool and slice off thin slivers of #10 solid copper wire then place them under
the set screw, you just have to do it once.
1/8" diameter brass rod works too.

[SSGOldfart]

A friend showed me an easy no-modification method to keep the sprue plate from loosening on a lyman mold. This probably applies to any mold that has a lock nut, where the lock nut (allen set screw) doesn't apply the right force to actually keep the sprue plate screw from turning occasionally. This has worked for me personally on two lyman molds and an ideal single cavity.

All you do is remove the sprue plate lock set screw (with sprue plate screw still in and threads visible) and insert one piece of #7 or 8 lead shot in the hole, then re-insert the set screw. The lead bites the threads and gives enough friction to make the system work for hundreds of casts without adjustment. Last week I cast 500 bullets non-stop in a mold that previously needed tightening every 20-30 bullets.

If you find that the set screw will not fit in after inserting the shot, either go to a smaller size of shot or flatten the shot and align it flat with tweezers in the hole to give the set screw room to thread in.

I wanted to pass on this idea as it is dirt simple, works great and doesn't make you alter your mold like filing a flat on the sprue plate screw.
Well I'll know if it works because I have two or three I didn't use often because they are a PITA to stop and tighten over and over, I've even replaced the screws before.

[blackthorn]

One of the little brass balls from an old light switch pull chain works well.

[Wayne Smith]

So does a small pinch of ultra fine steel wool.

[gwpercle]

I was going to try the lead shot on a mould set screw , been using it for years on die set screws , but got to thinking....will the shot melt....the mould will be getting HOT ! So I had some soft aluminum wire, clipped off some small pieces and used them in place of lead shot, it's working !

Wayne Smith is right about the steel wool, I had some Lee moulds that were driving me insane with the sprue plates coming loose, a few strands of 0000 steel wool wrapped around the lower threads and those screws have not loosened up one bit. In fact I went to unscrew one and it was so tight I decided to just leave it alone. None have loosened after the steel wool treatment. I have no idea why this works but it does.

Gary

[rwadley]

The newer RCBS moulds come with a small brass disc behind the set screw.

[DLCTEX]

Short brass pins from a lock tumbler work great for me. I rekey locks often so have a good supply. A locksmith should have them.

[drifterdon]

I need to try the steel wool fix on my Lee mold. I have to retighten the sprue plate screw after every 3rd or 4th pour.

[country gent]

I have also after adding the copper slug or lead shot went to a 1/8" longer set screw and added a small lock nut to it against the blocks to help keep the set screw from loosening. You need to make sure the sprue plate clears the nut though. It helps and the one mould I had issues with ( even after the copper slug was added) hasnt needed to be reset since adding the lock nut and longer set screw.

[sealer]

I have used the steel wool trick before.
Dennis

[Wayne Smith]

Interesting. I simply ment a little ball of fine steel wool to replace the lead shot or copper.

[Walkingwolf]

I have not had a problem with my Lee molds, once the molds are hot enough the screw does not back out.