Lee 6-cavity Mould Fix

[Rockindaddy]

Have alot of boolit moulds! Lyman, Magma, RCBS, H&G, and Lee. Most iron moulds are expensive. The aluminum alloy Lee moulds turn out a quality boolit. They are a bit more fragile than the iron moulds. The 6-cavity Lee moulds crank out a good quantity of boolits in any casting session. My wrists get sore handling the 4-cavity Lyman and Hensley & Gibbs heavy iron moulds. Lee 6-cavity moulds are light and easy to handle. There is a weak link in the Lee 6-cavity moulds. The screw plate screw tends to strip out the threads in the block or they shear off. Drilling out the broken thread in the block is a pain. The sprue plate shoulder screw is a 10-32 Calling Lee company and waiting on the phone for 25 minutes for customer service resulted in no fix for the problem. I measured the hole in the sprue plate @ .320 in diameter. The largest thread you could tap in the mould block is 5/16x24 I found a 3/8" 6 grunt bolt to chuck up in the lathe and turned it to the .320 in diameter. Had to reduce the shank to .312 to cut a 5/16x24 thread. Drilled the aluminum mould block out with a letter I drill and tapped a new thread in the block. The little wavy thrust washer applies just enough force on the sprue plate to keep it secure and tight on top of the mould block. I found Blaster Company now has spray graphite that works great on boolit moulds. I realize not every boolit caster with a broken mould does not have a lathe handy but that is what friends are for! My suggestion to Lee was to turn out a 5/16 shoulder replacement sprue plate screw and offer it as a retro fit.

[deces]

Are you spraying that graphite in the mold cavities?

[Dusty Bannister]

Some just utilize the thread repair kit and can use the same bolts.

[Harter66]

I've been doing this since about 1 yr before join date .
I have Cramer , Herters, LBT , Lyman , Lee , Mountain , NEI , NOE , RCBS, Lachmiller, M-P and several without anything to track down a maker . I've never stripped a screw hole or broken a screw or bolt off .

I have relieved a couple of second hand plates where the sprue bolt had become too short . I did recently have an NOE aluminum squirt an alignment pin out . I've "fixed" a couple of Lees that wouldn't close and line up right , by restoring the slop , which is very needed in that design, but goes away at temperature.

I think the biggest thing wrong with Lee moulds is the owners that want them to feel and work like moulds costing twice as much. The fact of it is that it just doesn't work that way .

It is a neat fix but time vs money you probably would have been better off with a helicoil insert and adjusting the stop depth on the top coil . I can't fault the over size bolt turn it down and rethread it method. Unfortunately you took the dead stop , set clearance factor out of the design and now you need a mechanical lock on the sprue plate hinge bolt . You had probably all ready done that though .

[Rockindaddy]

Yeah! Spray the graphite on the wear surfaces and the cavities. The boolits fall out! A company called ZEP also makes a spray graphite that works good too. Oil on a mould is terrible. Makes wrinkle boolits.

[Rockindaddy]

I have broken several Lyman sprue plate screws. Lyman has a set screw that allows you to set the sprue plate tension. Loosening the set screw most of the time allows for the easy removal of the sprue plate screw. When they snap off you just have to drill the screw and remove it. Lyman makes replacement screws. They sell a kit. Maybe I am just too hard on my moulds! I cast a lot of boolits.

[oldhenry]

It has been my experience that the set screw against the sprue plate screw distorts/damages the threads on that sprue plate screw over time with adjusting the tension tighter and tighter. Then when the mold needs a major cleaning (requiring a major disassembly) the removal of the screw plate screw (with the damaged threads) ruins the sprue plate female threads within the mold block.

Lee needs to remove the threads in the area of the set screw contact & the problem will be solved. If I had a small lathe I'd do so before use. Rockindaddy's solution is commendable (I like the larger dia. bolt) & can be improved by removing the bolt threads @ set screw contact (obviously he has a lathe).

[deces]

Yeah! Spray the graphite on the wear surfaces and the cavities. The boolits fall out! A company called ZEP also makes a spray graphite that works good too. Oil on a mould is terrible. Makes wrinkle boolits.

Thanks for the response, I'll give it a try with the can I have. That graphite spray is messier than spray paint.