Honing out a sizing die

[JayinAZ]

When I started lurking on here 2 or 3 months ago I remember finding an article about a good way to hone out a die. It was either here or on castpics. Of course I didn't bookmark and now I can't find it. Can someone point me to it?

Thanks :)

[Scrounger]

How to hone a size die
by Buckshot



Oft times we find ourselves needing a bit more girth in a bullet to please a particular firearm. And, as sometimes happens the size we need isn't available or we don't want to pay for the custom manufacture of one. You can do this yourself and accomplish very accurate results for just a few cents worth of materials (not counting the size die) and a bit of time.
What you will need:
1) A size die that is as close as possible to what you want
2) A length of steel rod that is close to 3/4 of the diameter of the existing die, and long enough to protrude at least 2" beyond both ends of the die.
3) Wet or dry emery paper of 320, 400, and 600 grit. If you do need to remove more than a couple of thousandths you should also include 220 grit. Actually the 400 will finish the inside well enough, but hitting it with a bit of 600 sure slicks it up.
4) Oil. Most any oil will do.

What you do:
The paper should be cut long enough to extend out either end of the die, almost as long as the steel rod. Wrap your starting coursest grit paper around the steel rod a couple times and apply some oil to the paper. Insert the covered rod through the size die. With just your thumb and a couple fingers on each end of the rod, roll it up and down your thigh (while sitting) applying only mild pressure. The reason for using a rod as large as possible, is to keep from tapering the inside of the die, by having a slender rod bend under pressure.

This will get your pants leg fairly well oiled up, so use old pants. Or you can staple a bit of cloth to a length of wood. Most any surface that the die can turn on is fine. I use a piece of mud flap screwed to a bit of 2x4, and clamp it in the vise, and it's a good working height.

Roll the steel rod occasionally as only a small portion of the paper is in contact with the interior of the die. You should also swap the die end for end every now and then to make sure the metal removal is as even as possible. Remember the throat of the die is tapered to admit the bullet and we're only wanting to open up the actual sizing portion of the die.

When you check your work you don't need to put the die back in the press. Just drill a hole in a board bigger than the bullet and place the die over it. Place a bullet in the die and tap it through. Remember to leave a bit of metal to remove for your polishing down to final size with the finer grit paper. The first time I did this I just took it down to where I wanted it without thinking of the finish. It works, but you do need a bit more effort to get the bullet in and out, and it just isn't the right way to do it!

Your existing plunger will still be fine in the honed out size die, unless you opened it up several thousandths. Even then it may still work fine, but you'll need to pay more attention to the lube consistancy and the amount of pressure you exert on the lube reservoir.

[JayinAZ]

That's the one Scrounger, thanks!

[quasi]

I use much coarser grits to start honing, especially if going up 4 or 5 thou or more. I have found RCBS sizing dies to be much harder than the Lymans.

[JIMinPHX]

How much are you looking to hone out? If it’s more than a thou or two, you might want to head on over my way & give it a spin in my lathe.

[JayinAZ]

Jim,

I need to take about .002 out of it. It's a Lyman marked .430, but the sized bullets come out at .431. My Model 24's throats measure .433. I appreciate the offer of the lathe, if you think it would be a lot easier that way maybe we could get together this weekend.

[IcerUSA]

A wood dowel with lapping compound in a chuck in the tailstock run into an ID of about anything spining at a medium speed works good on a lathe .

Keith

[mtgrs737]

JayinAZ,

I have noticed that when I size a boolit in my Star the boolit measures .4515" just out of my .452" star die. Then after 8 hours or so the same boolit will measure .452". The harder the alloy the more spring back you may get or so I understand. So you might want to ease up to the diameter you would like in a couple of steps and do a size and wait 24 hours to see what the springback gives you. Good luck!

Mtgrs737 :castmine: