Enlarging Boolit Sizing Die

[TCLouis]

Buckshot et al.
Do you drill, ream and polish out the sizing die?
OR do you spin it in the lathe and open it up with abrasive paper?
Hardened or cold rolled pin for the die?

Full of questions with NO answers!!

I want to go to 0.460" from 0.457"

[cast-n-blast]

TC, I've polished out a few sizing dies using the split steel rod, emery paper, and hand drill route. Just cut a vertical slit in a 3/8" steel rod about 1 1/2" long. Now cut some 320 grit emery cloth into 1 1/2 " strips about 8" long. Thread it in the slit of the rod and wrap tightly until it is large enough for snug fit in the sizing die of choice. Now chuck the split rod in your drill anf go to it.
I'd be more inclined to buy a .459 die and polish that out as it is less work and the push rod of the die will be a closer fit. If there is too much space between push rod and die, bullet lube will squeze thru and out the bottom of die.

[454PB]

I use a split bolt and abrasive as mentioned above. I have a lathe for this, but I don't see why a drill wouldn't work. Another method I've read about is placing a mandrel through the die with abrasive, then rolling the die on your thigh while holding the mandrel stationary.

If you were doing a lot of this, then a reamer is the answer. I've only built a dozen or so sizing dies, so I do it the crude way. I suggest you go slowly and measure progress by "slugging" the die. It's easy to overshoot!

[krag35]

I just opended up a Lee push thru from .430 to .432 today. I used a split brass rod emory paper and a drill press. It takes longer than you think, but it's not that hard. Keep it oiled and the die moving so it don't get out of round.
krag35

[TCLouis]

that I plan to chuck the die in a lathe and open it up.
I may well cut a couple of rings in the rod (is that the H or I in H&I) and put O-ring or two and leave it undersized.

If one was making their own H&I die I guess they could drill fewer holes for lubricant if the choice of boolits to be lubed was limited!

Anyone out there have any idea what kind of steel they are made from?

[454PB]

The Lyman sizing dies are fairly soft, the Star dies are extremely hard. When I make mine, they are from mild steel. Some of them have sized many thousands of boolits, with no dimensional change. I have several of the Lee push through dies, but haven't altered any, so I can't say how hard they are.

[Buckshot]

................Spinning the die on a split dowel with abrasive paper (you hold the die) is fine for a couple thousandths. Beware you don't oval the die or bellmouth the bottom. The more you have to remove, the more likely the mishap.

If you can spin the die in the lathe with the dowel in the tailstock you're miles ahead. If you have to go much, changing out paper can be a pain. You can also re-charge the paper with valve grinding compound, but the paper WILL eventually wear away. The paper and the valve paste are both designed to break down into finer and finer bits, which is a good thing.

To be aggressive diamond paste is the way to go but a 2 gram tube can run about $32. Diamond does not break down and keeps cutting.

If it's just a once in a while thing then the dowel in the tailstock is the way to go. A good thing to do is to place a cloth patch under the paper. Put the patch up next to the slot in the dowel and wrap both the paper AND the patch around the dowel one complete turn. If it's too loose use a longer piece of paper for 2 turns.

The cloth patch sucks up a lot of room but also compresses some and will keep a good even pressure on the abrasive paper. Use WD40, paint thinner or lamp oil on the paper when turning. It will help keep the abrasive paper clean so it can cut and it lubes. The die can also get really hot if you're holding it!

..............Buckshot