A little help please

[brotherdarrell]

:veryconfu I am very confused and could use some ideas. Yesterday I cast a little over 600 Lee 452-200-RF from a six cavity mold that has probably dropped close to 8K boolits over the years. When dropped from 50/50 ww/pure the boolits have always dropped around .4515", with a little bit of frost. They are also water dropped. This go round I was using some mystery alloy that air cools a little over 7bhn and water drops around 12bhn.
55334
I have cast several different molds with this alloy with few difficulties. This casting session resulted with diameters all over the board from .440" to .450" when miced opposite the parting line. The crazy thing is most of the diameters across the parting line are very close to .451". I am also getting a little shinier frost. Weights on the small diameters are about 2-3 grns. less. Fill out seams to be good, but if the mold gets a little too hot it almost appears as if parts of the boolit slumps when released from the mold; imagine a mud slide. There were also a couple of boolits where the nose fractured when the mold was opened even though I was running the pot cooler than normal and was not casting fast. Sprues were setting up in about 3 - 4 seconds, I would wait about a 2 counts then cut. Boolit bases were solid.
Good diameter
55335
small diameter
55336
good
55337
small
55338

Sorry for the poor pics, it's the best my poor camera can do. Other than turning down the pot a little my casting routine was no different than any other time. I now have over 600 boolits that need to be re-melted. I would like to not have a repeat occurrence if possible.

Any help would be greatly appreciated.

brotherdarrell

[runfiverun]

i had a mold suddenly do this to me part way through a run and i didn't catch it till after the fact.
turned out i got a little lead in one of the holes for the alignment pins it shifted the mold halves off center just enough to affect the diameter.
i could "see" it as a deep line at the parting line on the boolits with my fingers.

[brotherdarrell]

Looking closely the boolits did show offset cavities. I could'nt see any lead around the alignment pins, but there were a few specks of lead on other places. I cleaned them up and it may have helped a little with the alignment. I tried a few gentle taps on the end of the blocks and it now seems to line up properly. Will cast some more today and see what happens. Thank you sir for the suggestion.

brotherdarrell

[Bwana]

A couple more things to check would be the alignment pin inserts having moved from where they were set in the molds (backing out). Another thing is peening of the mold block by the alignment pin guide at the handle end of the mold. I have had both of these happen to much used Lee 6 cavity molds. The solution to the first is the reset the pin or guide, and on the second trim off the peened "bump" with a small sharp knife or file.

[brotherdarrell]

Well, this mold for sure has an alignment issue, and it is not related to lead on the blocks now. It would appear that the alignment pins are loose and are not lining up correctly. With the mold closed I can see that the two sides are not even on the end of the mold. I can gently persuade them back where they belong, but as soon as I close the sprue plate the pressure on the sprue stop moves them back out of alignment.

Bwana - I will try your idea. If that does'nt work it may just be easier to get another mold. I don't shoot a lot of these boolits, but the guys I make these for pretty much keep me supplied in lead and it would be a small price to pay to keep them happy. I do hate to give up on a mold that is already paid for though.

Thanks for the ideas.

brotherdarrell

[runfiverun]

as a last resort, you could try lapping the cavity's a bit bigger/rounder in their new alignment.
kinda if you can't beat it,fix it how it want's to be type thing.
you won't be out nothin but time even if you have to buy another mold,and learning how to lap a mold is a good skill to have.

[brotherdarrell]

I have lapped a few molds with varying amounts of results. In this case it might be easier to just beagle the mold since the small diameter is opposite the parting line. Either way due to the fact that I am trading boolits for lead I do want to make sure that the boolits I am providing are the best I can make. I don't mind shooting ugly boolits but those for trading purposes I prefer to look somewhat tolerable. In the last 6 months these guys have provided me with a little over 600 lbs of lead. I see no reason to get cheap on them now. By the same note, if I do have to lap a mold this would be a good candidate if I am unable to fix it otherwise. Thanks again.

brotherdarrell