Trying to salvage a 7/8 Lee Key Drive Mold

[KrakenFan69]

I picked up a 7/8 oz Lee Key Drive slug mold. I got one good session casting with it then something happened and its kinda buggered up. The alignmnet ring in the pin is very rough and there are a couple of burrs on the top of the mold under the sprue plate. I never noticed it when it happened. Just suddenly the slugs wouldn't drop out. I believe the pin backed out and I missed it and closed it with them not aligned and that may have caused the damage. I really don't care for the pin design and got to thinking, what if I had a pin like my Russian Paradox mold or Lyman 525? I drew this up quickly and was wondering what you esteemed gentlemen think of the pin design and idea as a whole.

230238

Thanks,

Kraken Fan #69

[pashiner]

I like it. It seems like it solves the problem of casting a factory-like foster slug in a usable diameter...unlike the much maligned lyman foster slug mold. I like the beefy skirt. I wonder if there's enough thickness there to avoid skirt collapse with soft-ish lead?

[KrakenFan69]

I specifically "designed" the pin to create a thicker skirt for that very reason!


Kraken Fan #69

[longbow]

Sprue plate lube on the pin and under the sprue plate should solve that sort of damage. Aluminum on aluminum tends to gall if it rubs. I usually use both sprue plate lube and powdered graphite on the few Lee moulds I have.

Running a diamond hone or very fine emery cloth or silicone carbide paper on a flat piece of bar over the bottom of the sprue plate edges to bevel or radius them smoothly helps too. Sometimes the lee sprue plates have sharp edges around the sprue plates.

Also, I find that just closing the mould results in the core pin not straightening out to align with the groove very well. I use my mould dowel to jiggle block gently as I close them so the blocks and core pin line up as the mould closes. Again, graphite on the pin contact areas also helps.

I have both the 1 oz. and 7/8 oz. lee moulds but neither shoots real well for me as is. Improvements are:

- to set the slug in a lubed form (I use CPVC pipe bored to suit) base up then fill with hot melt glue so there is an extension like attached wad of about 3/8". This adds a lightweight material to the slug making it effectively more nose heavy. That helped considerably with accuracy.
- size the slug down to remove the taper then paper patch back up to snug fit in wad. This also improved accuracy for me. Best will likely be a combination of these two: size down to remove tape, add glue fill/attached wad, paper patch to snug fit to bore with chosen wad.

Ranch Dog has noted that the Lee slug design has center of pressure behind center of gravity so making the slugs unstable. Seems like an odd thing to do and an easy thing to fix by lengthening the slug a bit or putting a bit more lead in the nose.

One fellow here used an epoxy to fill the key slot in the pin and eliminate the "drive key". He says this improved accuracy for him. Here we go, I found the thread:

http://castboolits.gunloads.com/showthread.php?368495-Modified-Lee-slug-success

Your idea is similar. I'd watch skirt thickness as it adds weight to the base of the slug. The skirt can be too thick. In my experience even very thick skirts distort unless filled or oven heat treated (so wheelweight alloy not soft lead).

I lean towards filling with hot melt glue and keeping skirts at about 0.100" thick. The change I'd suggest with your design is to make the HB pin conical with radius top as you have. this will thin the bottom edge of the skirt more and keep more weight forward and also give better release from the pin. I'd use at least 3 degree taper on the pin so tangential line from radius 3 degrees outward making the pin more conical. The slug will stick to a pin with cylindrical sides.

Just put some taper on that pin and you should be good to go.

Your idea looks a lot like the old Nessler Balles used in the Crimean War and even in the American civil war.

Longbow

[gpidaho]

Galling on Lee moulds and getting the bullets-slugs to release from the pins was a problem I had until I was told about using dielectric silicone grease as a mould lube. Used sparingly it's hard to beat on both the HP-HB pins and between the blocks and sprue plate. I still use two cycle motor oil on the mould block pins to prevent any kind of buildup. Gp

[KrakenFan69]

230252

Version 2


Kraken Fan #69

[longbow]

Version 2 looks like a winner!

The skirt may be a bit thick but it looks like a nice HB cavity and looks like it should be nose heavy.

I think you will still have to oven heat treat or fill the cavity even with that thick skirt but it looks good and if ACWW doesn't distort at that thickness you really have a winner..

I've been thinking of seeing if Lee will supply extra core pins that do not have the drive key slot. They will provide core pins but not sure if they would interrupt their production to remove a pin or two before slotting. It won't hurt to ask though. I'd like to remove the drive key and cut the nose of the pin a bit to make the slug look more like your proposed slug. I think getting rid of the drive key will fix the CG/CP issue Ranch Dog pointed out.

I think your slug will be better than the stock Lee.

Longbow