Altering a sizer die

[augois]

I have a .264 lyman sizer die that I don't use, but I would like to have a .268 or
.269 die. Would it be possible to ream the existing die open that much without any ill effects?

[rusty marlin]

A reamer won't cut it as the die is just as hard. I would lap it out.

Take a piece of 1/4" brass rod and slit it for an inch or so with a hack saw on one end. Spread the ends with a screw driver and smear some valve lapping compound on the brass. Hold the die in a padded vice and run the lap in and out with a hand drill or drill press. Adjust the spread of the lap and replenish the lapping compound as needed. Use a set of pins or an inside micrometer to get the size right, the ID tips on calipers won't be accurate enough at that small size.
Rusty

[scb]

I recently bored a .357 Star die to .368 with a carbide boring bar. Worked well.

[GabbyM]

if you take .004" out of a lyman die the punch will be loose and lube will ooze out .
You may be able to live with it.

[pjh421]

I recently honed a die for my Star from .3580" to .3586". This essentially eliminated leading in the cylinder throats of two of my .38 wheelguns as well as everything downrange of that.

I wrapped some 220 grit wet or dry around a brass rod, inserted it into the die bore and rolled the die body on my pant leg, holding the brass in both hands. It took a while but I got the exact result I wanted by "sneaking up" on the diameter.

Every once in a while I would knock a .38 casting through the die with a bit of swage lube on it and then measure with a micrometer. It was cheap and low-tech but it worked so well.

When I got to about .3585" I took the bore up to a finer polish, eventually using 2000 grit wet or dry. Pretty darned nice, and I learned it here.

Paul

[scb]

GabbyM's right. No longer having a sizer with a bottom punch I didn't think of that. You could however turn up a new bottom punch to fit. Making one would hardly even be classified as a project. Assuming you have the tools.