Lyman Mold Tight Allignment and Opening.

[Hanzy4200]

I have a older Lyman 2 cavity 9MM Makarov mold that I bought used. It ran well for a good while. At some point, it started to become difficult to close completely. It also sticks when you attempt to open the mold to drop your bullets. Should I press the alignment pins in slightly with a vise or try to polish out the alignment pin holes?

[country gent]

First off is to look for "wear/rub" patterns on the pins and holes. This gives you an idea where the problem is at. Next with a good magnifying glass look for burrs and or dings in the hole and on the pins. Here lightly remove any burrs or raised metal seen. The mould was running food and the pins should be set last option is to move pins do this very carefully and in small increments.

[eveready]

Have you been lubricating the pins and bushings regularly? If not get some full synthetic two stroke motorcycle oil. This stuff does wonders on the pins and bushings.

[poppy42]

Do the molds close completely without the handles? (No light leeks). If so it’s probably not the mold pins. Honestly the first thing I would do was try changing handles

[Hanzy4200]

Do the molds close completely without the handles? (No light leeks). If so it’s probably not the mold pins. Honestly the first thing I would do was try changing handles

I have factory Lyman handles, and altered LEE handles. That was he first thing I tried. No go.


Country Gent, the only deformity I can see is slight flattening in the furthest pin. I can't remember if it was like this when I purchased it or not. The trouble with having 20+ molds. Hard to keep track of all the little quirks.
Poppy42, I can get them closed tight, but with way to much pressure, and equal pressure in opening. My hand would be cramping in 5 casts.

Eveready, yea I have been using 2 stroke oil. Was initially using beeswax as some older guys instructed, but you are very right. This stuff is WAY better. No residue.

[OS OK]

Sounds like burnt wax and oil has collected in the female side of the alignment holes and is preventing the full closure.

[rintinglen]

Clean the mold thoroughly with carburetor or beak cleaner. Then squeeze the pins in a smidge and try the mold again. Don't sweat it if you push the pins in too far, you can drift them back out with a hammer and a punch. I don't have a good explanation as to why this sort of thing happens, but it does. I have a 2 cavity RCBS 38-150 kt that has pulled that stunt with me. It is easily resolved.

[Bent Ramrod]

I find that when a mould suddenly gets hard to close, it’s because I’ve shut the thing carelessly in the “heat” (get it? *rim-shot * :mrgreen:) of a casting session. This throws up a tiny burr on the edge of one of the locating holes on the faces.

It’s very hard to see this sometimes, even with a magnifying glass. My diagnostic tool is my trusty set of Quality Import pin gauges, although a drill shank of the proper size works too. The gauge or drill, inserted from the back side, will push through one of the holes easily, but hang up on the mouth of the other. Or, if it’s not drilled through, it will have difficulty going into one of the holes from the front and not the other.

My remedy is to reverse the drill that fits the hole best, and kind of “peel” or “core” the lip on the offending hole by hand until the drill slides through. I do it from the backside of the through holes and (very carefully) from the front if I have to. From the front, I use a smaller drill and gradually get enough of the burr cut away until the proper size drill only has a tiny amount to remove. I hold the drill in a pin vise or loose chuck and never use power. You can hold the drill in your hand if your fingers are strong enough.

Flattening on the rounded tips of alignment pins is pretty normal; means they were a little tight when driven in for adjustment. If the mould closes normally, no harm done. In my experience, the locating pins tend to recede into their holes with use, rather than coming further out, pushing the blocks apart. The mould will close tightly with receded pins, but the blocks will slide back and forth against each other and the casting halves will be slightly out of alignment.