lapping out a sizing die

[x101airborne]

What are yall's suggestions for lapping out a sizing die? Besides general reloading tools, all i really have is a good drill press. I have several dies (lyman) that could stand to be .001 - .002 bigger. Thanks in advance.

[littlejack]

x:
I have lapped one Lyman .314 out to .317. It worked very well. I wrapped some 600 grit
wet/dry paper on a small shaft with a slot to hold the paper. I chucked it up in my drill press
and ran the die up and down until the desired inside diameter was reached. Not a problem.
Jack

[76 WARLOCK]

It works very well, I use a solvent like paint thinner to lube the wet or dry paper. Right now I have a .457 I just took it out to .459 it took about an hour.

[randyrat]

Or use 400 grit sandpaper and make a dowel with a split in the end. Roll your abrasive paper around the dowel stick it in the die.
Now place you die on your leg, hold the dowel with the other hand and roll it back & forth on your leg. When you get close, change to 600 grit paper to make it smooth.

[ButchC]

I've heard valve grinding compound in the lube grooves works well. haven't tried it myself as if you lap em out they're gonna leak more. as obvious as that may seem it took me a moment to process it before i passed on the idea to see if the next gunshow had a couple thousandths up.

[JIMinPHX]

My best advice is to try to trade the die you have for one of the proper size on the swappin & sellin part of this board. The factory finish is hard to beat & when those things come from the factory, the holes are just about perfectly round.

As a second choice, given the equipment that you have to work with, I would recommend an abrasive honeing tool like this - http://www.brushresearch.com/product-line.php?line=1

My third choice would be the sand paper trick. If you go that route, use wet/dry paper. Use it dry first to take off material & then use it wet to get a better finish. Wetting it with a little oil or polishing rouge will give you your best final sandpaper finish.

[fredj338]

If you can find a machine shop that does cylindriacal grinding, they can fix you up pretty quickly. I have a fieind that owns such a shop, does them for me for free.[smilie=w: Maybe I should get him to set up a little side business?

[leadloader]

it is easy i used 2000 grit paper,and remington gun oil maybe overkill but i dont think so.. i took a lee .311 die to .312 took a few doing the dowel rod leg method but results i were after were acheived.. all though my die did not end up perfectly round . the out of roundness was very minor but there none the less... i would sand then clean then size a few measure and repeat till i got the diameter i was after...

[geargnasher]

I've done several using 400-grit emory paper/split dowel/drill press, finish with 600. Thin oil or solvent is a must, and it takes a lot more than you think it might to get .001" It will make the die leak around the bottom, but it also gives the air someplace to go. I never worry too much about .0002-3" or more out of round, often they are that far out from the factory. Once the boolit hits the bore it will be whatever shape it needs to be anyway.

Gear

[44man]

Done with a slit rod, a die can come out more round then first made.
I wrap for a force fit in the die, the just spin with an electric hand drill. Clean and size a boolit. Keep going until you get what you want.