Mold Adjustment Question

[cabezaverde]

I have a couple of Lyman molds that do the following:

As the mold comes up to regular casting temp., it "sticks" a bit when trying to open it. I get it open by jiggling the handles a little while pulling them apart gently. The mold does not do this when cold, and does it more as it heats up.

Once the mold opens, the bullet drops freely, and everything else seems normal. Any ideas on the possible cause, as well as any fixes. I am thinking drive the pins in a bit for shallower engagement?

Thanks for any experience out there.

[Bret4207]

Chancs are the alignment pin holes have burrs on them. I'd deburr the holes and lube them. Should help. Depending on your brand of case mouth deburring tool it might fit.

[rmb721]

Try a little of Bullshop's lube on the pins and alignment holes. That works for me on Lee six cavity moulds.

[e15cap]

Aounds like the pins need adjustment. Roger

[cabezaverde]

Try a little of Bullshop's lube on the pins and alignment holes. That works for me on Lee six cavity moulds.

Done that one.

[IcerUSA]

Drive the pins in a little , I take the mould off the handles , tap pins in , check for slop by wiggleing the two halfs together as you don't want any slop , if you get slop you over did it . Just use a punch from the back side to drive the pin out abit . I've had to do it with most moulds I have , Lee, Lyman , RCBS , and Seaco's .

Keith

[montana_charlie]

1. Check the fit of the mould halves in the handle jaws. Make sure that the jaws don't bottom out in the mould slots (at the front and back of the blocks) when the mould is closed tightly.
Check them cold, then check them when hot. Heat-expanded metal might be binding a bit, which can put side pressure (on the front or back) of the alignment pins...making them stick a little in the mating holes.

2. If nothing is close enough to cause actual binding, watch how the blocks separate as you open the handles. If the backside of the mould cracks open first (the side toward you) try pushing against that point (with your sprue knocker) as you open the handles. That should make the front side try to open first, and can eliminate the 'stickiness' (also caused by front or back side pressure on the pins).

3. Watch your block halves when you open the handles to see if the bottom of the mould tries to crack open first. This can happen when the handle jaws are thinner than the mould slots (like using RCBS handles with a Lyman mould).
The cure is to lay the mould on a flat surface as you open the handles, or swing the sprue plate all the way around (after cutting the sprue) so it lies across the tops of both halves.
It will keep the halves from 'sagging down' and prevent the side pressure (on top or bottom of the alignment pins) from feeling sticky.

The thing about alignment pins (assuming no burrs are present) is that you want a pin to back out straight when it leaves it's mating hole...just as you want your car to come out straight when you back out of a garage.

CM