Johnw...ski
03-30-2008, 10:39 AM
I received my new Lyman mold Friday and immeadiately had to try it. It is a 457132 Postell and it threw boolite right on .458 dia. and since I need .459 I was not happy.
After giving Dave at Buffalo Arms where I bought the mold some grief and
e-mailing Lyman who never responded I decided to take matters into my own hands.
I am sure I wasn't breaking new ground, but came up with the idea of mounting one of the boolits on a mandrill (see picture 1). I then loaded the bullit with 240 grit diamond compound (see picture 2) and with the drill press set at it's slowest speed I closed the mold on the lap I had made, the drill press was off at this point
(see picture 3). Holding the mold handles I turned on the drill press and ran it for 10 to 15 seconds. I recharged the lap and repeated, then cleaned the lap and recharged with a finer diamond compound. I went to finer compounds up to 600 grit.
I cleaned everything up and reassembled the mold and tried casting a bullit.
The bullits dropped from the mold much easier then before and measured .4595 on the drive bands. Success, but I wasn't ready to leave well enough alone.
The bore rider area measured only .448 so I did a little stoning with some oil and
various grits of polishing stones. Then I made another lap and releived the grease groves and filed the driving bands down so the sides of the grease groves now located the lap but the bottom of the grease grooves and driving bands were not touching. I loaded the lap with compound and gave the mold a final polish (see picture 4). After casting some more boolits I measured the bore riding area and found I had gained .002 it now measured .450 still .003 small but I decided not to push my luck and will try sizing and loading some of these boolits to see how they perform at the range.
This whole process only took an hour and should be well worth it. I was very surprised to see how quickly and easily the drive bands were opened up.
John
After giving Dave at Buffalo Arms where I bought the mold some grief and
e-mailing Lyman who never responded I decided to take matters into my own hands.
I am sure I wasn't breaking new ground, but came up with the idea of mounting one of the boolits on a mandrill (see picture 1). I then loaded the bullit with 240 grit diamond compound (see picture 2) and with the drill press set at it's slowest speed I closed the mold on the lap I had made, the drill press was off at this point
(see picture 3). Holding the mold handles I turned on the drill press and ran it for 10 to 15 seconds. I recharged the lap and repeated, then cleaned the lap and recharged with a finer diamond compound. I went to finer compounds up to 600 grit.
I cleaned everything up and reassembled the mold and tried casting a bullit.
The bullits dropped from the mold much easier then before and measured .4595 on the drive bands. Success, but I wasn't ready to leave well enough alone.
The bore rider area measured only .448 so I did a little stoning with some oil and
various grits of polishing stones. Then I made another lap and releived the grease groves and filed the driving bands down so the sides of the grease groves now located the lap but the bottom of the grease grooves and driving bands were not touching. I loaded the lap with compound and gave the mold a final polish (see picture 4). After casting some more boolits I measured the bore riding area and found I had gained .002 it now measured .450 still .003 small but I decided not to push my luck and will try sizing and loading some of these boolits to see how they perform at the range.
This whole process only took an hour and should be well worth it. I was very surprised to see how quickly and easily the drive bands were opened up.
John