MBTcustom
12-30-2015, 01:15 AM
So here I have a beat up old mold that I traded for here on the forum. I have heard this is a fairly good bullet design, but this mold looks like five miles of bad country road, and casts like it too.
156788
156789
156790
Yeah, it's pretty bad.
Here are the problems that required a solution:
1. The mold blocks were not lined up. This could have been caused by the previous owner's propensity for opening the mold and tapping it on the blocks with a ball peen hammer or equivalent.
2. The bullets dropped were of the old style gas check shank, and thus, were too large to accept a modern crimp-on gas check.
3. The bullets cast of my House alloy were too small.
4. The internal finish of the mold was like the surface of the moon. Undoubtedly the previous owner also was under the common misconception that "smoking" the mold with a match or some such does some earthly good (goes right along with the ball peen hammer IMHO) and when the mold rusted, it was not even, and the soot probably helped hold the moisture longer than usual.
5. The bullets were a bear to get out of the mold when casting.
So I decided to "Leement" (or perhaps Lyment?) the mold by lapping it, and I thought some might find this process helpful. In the following description, you will see me reference my lathe and it's use in this process. The lathe makes it easier, and I use it because it's available, but an enterprising individual will find that a drill press and a file works just as well if you put your mind too it.
I started by getting the mold heated to operating temperature and casting a few bullets that were then measured with a micrometer. The sizes obtained were .4559 X .4581
156791
156792
It is important to measure what you have before you go changing something so that you know how much you changed it.
I also measured the gas check shank and found it was already too big, so I wanted to even it out and make it round but nothing past that. The gas check shank measured .433 while the Hornady checks measured .427 ID.
I took a bullet from the few that I cast, and I put it in the lathe and drilled it with a #7 size drill bit, which is the tap drill size for a 1/4-20 thread. I drilled it about 3/8" deep.
156793
Then, I put the drilled bullet in the mold and clamped tightly in order to hold it while I tapped the hole with a 1/4-20 HSS tap.
156794
Then a 1/4-20 X 2.5" socket head bolt was screwed into the threads, lapping compound was added to the mold, and the bolt was driven with a DeWalt cordless drill till it was spinning freely in the cavity when the mold handles were held firmly.
156795
The mold was then cleaned with carburetor cleaner, heated up by dipping the corner in the molten lead, and cast with till good consistent bullets were falling out of it ( I noticed emediately that problem #5 was corrected, as the bullets fell from the mold when it was opened.)
The bullets were swished in a cup of water with forceps to cool them and measurements were made. I was happy with the roundness of the gas check shank, but the driving bands were still too small, so I made another lap from one of the bullets I just cast, only this time, I turned off the GC shank so that it would not be enlarged any more.
156796
The new lap was prepared in the same way as the previous one and it was used again to lap only the nose and the driving bands.
156797
The mold was cleaned again, and was cast with a third time. This time the smallest diameter of the bullet could be measured at .4575 and the largest was .4587
156788
156789
156790
Yeah, it's pretty bad.
Here are the problems that required a solution:
1. The mold blocks were not lined up. This could have been caused by the previous owner's propensity for opening the mold and tapping it on the blocks with a ball peen hammer or equivalent.
2. The bullets dropped were of the old style gas check shank, and thus, were too large to accept a modern crimp-on gas check.
3. The bullets cast of my House alloy were too small.
4. The internal finish of the mold was like the surface of the moon. Undoubtedly the previous owner also was under the common misconception that "smoking" the mold with a match or some such does some earthly good (goes right along with the ball peen hammer IMHO) and when the mold rusted, it was not even, and the soot probably helped hold the moisture longer than usual.
5. The bullets were a bear to get out of the mold when casting.
So I decided to "Leement" (or perhaps Lyment?) the mold by lapping it, and I thought some might find this process helpful. In the following description, you will see me reference my lathe and it's use in this process. The lathe makes it easier, and I use it because it's available, but an enterprising individual will find that a drill press and a file works just as well if you put your mind too it.
I started by getting the mold heated to operating temperature and casting a few bullets that were then measured with a micrometer. The sizes obtained were .4559 X .4581
156791
156792
It is important to measure what you have before you go changing something so that you know how much you changed it.
I also measured the gas check shank and found it was already too big, so I wanted to even it out and make it round but nothing past that. The gas check shank measured .433 while the Hornady checks measured .427 ID.
I took a bullet from the few that I cast, and I put it in the lathe and drilled it with a #7 size drill bit, which is the tap drill size for a 1/4-20 thread. I drilled it about 3/8" deep.
156793
Then, I put the drilled bullet in the mold and clamped tightly in order to hold it while I tapped the hole with a 1/4-20 HSS tap.
156794
Then a 1/4-20 X 2.5" socket head bolt was screwed into the threads, lapping compound was added to the mold, and the bolt was driven with a DeWalt cordless drill till it was spinning freely in the cavity when the mold handles were held firmly.
156795
The mold was then cleaned with carburetor cleaner, heated up by dipping the corner in the molten lead, and cast with till good consistent bullets were falling out of it ( I noticed emediately that problem #5 was corrected, as the bullets fell from the mold when it was opened.)
The bullets were swished in a cup of water with forceps to cool them and measurements were made. I was happy with the roundness of the gas check shank, but the driving bands were still too small, so I made another lap from one of the bullets I just cast, only this time, I turned off the GC shank so that it would not be enlarged any more.
156796
The new lap was prepared in the same way as the previous one and it was used again to lap only the nose and the driving bands.
156797
The mold was cleaned again, and was cast with a third time. This time the smallest diameter of the bullet could be measured at .4575 and the largest was .4587