Open up a Carbide Sizing Die in 15 minutes

[Mal Paso]

After figuring out boolit fit I've settled on .431 boolits for my 44 Mags and have been working to get reloading dies that match my boolits. I bought the RCBS Cowboy set but the sizer was too small. I had previously opened up a Lee Carbide Sizer so I knew what size I wanted but this method is way faster than my previous post.

Someone here posted a link to brass hole laps which I couldn't find but it got me thinking. K&S Engineering sells Precision Brass Tube with .014" walls in size increments of 1/32" and I have all kinds of tube resizing equipment. Mostly RCBS & Hornady. I bought a 12" length of 7/16"OD and one 13/32" OD brass tube at the local craft store. I cut the 7/16" just long enough to go all the way through the die with a roller cutter which slightly crimps that end. I used my Lyman M Die to open the other end of the tube. I cut a slightly longer piece of 13/32 and slid it inside the 7/16 until it contacted the crimp and used it to push the 7/16 through the die I wanted to enlarge. With brass spring back that made the bell end .002" larger than the die. I also left the smaller tube inside the 7/16 for strength in the drill chuck while polishing. I slid the lap through the die, chucked it in the drill. I smeared a dab of 325# Diamond Paste on the tube slowly pulled it through the die, drill at medium speed. The first pass took it from .4455" to 4485" and a couple light passes brought it to .4495" and it took 10 times as long to tell it as do it. Brass Tube (reusable for other projects) $8, Diamond Paste 8 cents worth from a $15 tube (Arrowhead Lapidary). Oh and having tube all the way through the die aligns the lap.

First pic is expanding the 7/16" tube.
Second is pushing the expanded part through the die.
Third is the whole assembly. The black on the tube is Diamond Paste made black by Carbide polished from the die.

Edit: Oops, Shaved brass on the first test cartridge, on the down stroke. I inadvertently sharpened the inside edge. I'll make another lap from 1/8 brass rod and break the inside edge of the die after work but Brass laps are very cool.

[sprinkintime]

After figuring out boolit fit I've settled on .431 boolits for my 44 Mags and have been working to get reloading dies that match my boolits. I bought the RCBS Cowboy set but the sizer was too small. I had previously opened up a Lee Carbide Sizer so I knew what size I wanted but this method is way faster than my previous post.

Someone here posted a link to brass hole laps which I couldn't find but it got me thinking. K&S Engineering sells Precision Brass Tube with .014" walls in size increments of 1/32" and I have all kinds of tube resizing equipment. Mostly RCBS & Hornady. I bought a 12" length of 7/16"OD and one 13/32" OD brass tube at the local craft store. I cut the 7/16" just long enough to go all the way through the die with a roller cutter which slightly crimps that end. I used my Lyman M Die to open the other end of the tube. I cut a slightly longer piece of 13/32 and slid it inside the 7/16 until it contacted the crimp and used it to push the 7/16 through the die I wanted to enlarge. With brass spring back that made the bell end .002" larger than the die. I also left the smaller tube inside the 7/16 for strength in the drill chuck while polishing. I slid the lap through the die, chucked it in the drill. I smeared a dab of 325# Diamond Paste on the tube slowly pulled it through the die, drill at medium speed. The first pass took it from .4455" to 4485" and a couple light passes brought it to .4495" and it took 10 times as long to tell it as do it. Brass Tube (reusable for other projects) $8, Diamond Paste 8 cents worth from a $15 tube (Arrowhead Lapidary). Oh and having tube all the way through the die aligns the lap.

First pic is expanding the 7/16" tube.
Second is pushing the expanded part through the die.
Third is the whole assembly. The black on the tube is Diamond Paste made black by Carbide polished from the die.

The Brass Laps, that you could not find are at McMaster Carr in LA, they are quite reasonable, in the 8 dollar range and you can expand them about a 1/64. Just in case you need to do others, and there whole catalog is on the internet. Sprinkintime.

[Mal Paso]

The Brass Laps, that you could not find are at McMaster Carr in LA, they are quite reasonable, in the 8 dollar range and you can expand them about a 1/64. Just in case you need to do others, and there whole catalog is on the internet. Sprinkintime.

Very cool! I will make a note this time. The tube was actually easier to get.

What astounded me was how well a brass lap of any sort works. A very cool tool I didn't know existed and I have hundreds of pounds of hole making equipment in steel, carbide and diamond.

[Mal Paso]

I had a brass shaving issue with a newly opened size die. I had sharpened the inside edge. Today I flaired a piece of tube with the expander die, coated the end with diamond paste, and used a rawhide mallet to drive the flair through the die. The brass sprung back on the inside. I pulled back against the inside edge of the die and turned it with my fingers. Once the edge was broken a hard pull removed the tube. No more brass shaving and the die size was not affected.

Just not enough rainy days this year to finish projects.