Die Clean up

In procuring hardware for my reloading set I was able to obtain at low cost 2 sets of older RCBS .357 dies with the steel sizing die. Sizing some brass resulted in gouged and scarred up brass that was even painful to hear going into and out of the dies. The dies were put aside and a “modern” carbide die was obtained and put to everyday use.

Not satisfied to leave well enough alone, based on searches here and elsewhere over time I have tried many of the DIY solutions on the better of the 2 dies and got it down to the point where the brass was left semi scratched and satin finished, so still not good enough. A chance search on cylinder hones sent me to the Brush Research Mfg website and their Flex-hone product line. Though primarily intended to be used for shotgun bores, revolver cylinders and rifle chambers it seemed just like the thing to use as an experiment to clean up the pair of crusty dies. Given the choice of 400 or 800 in pistol length I erred on the cautious side and got the 800 figuring the finer grit would have less chance of ruining the dies in a hurry. I sized a few sacrificial pieces of brass and took measurements to have a record for before and after measurements.

I chucked up the hone in my drill press, lubed everything down and went to work at 375rpm the lowest my press will go, feeding the die up and down the brush at an even stroke like honing an engine cylinder. Brake cleaner was used to remove the oil and alcohol and patches were used for a final cleaning. The dies were pre-lubed and a pair of pieces of brass were sized. After the first couple of try’s the scratches and scoring was reduced and measurements taken, but the cleanup was not progressing along fast enough. I consulted the instructions and upped my speed to 975 rpm, the manufacturers recommended speed is 1000-1200 rpm but my drill press jumps from the 975 to 1350 and I again erred on the slower side.

The results were much better and after a few more hone/clean stages and without any other “polishing” the dies now produce acceptable brass and cases size with much less effort. Having never used steel pistol dies I am not sure how “clean” the sizing is compared to carbide dies. The worst of the two dies could still go thru a bit more honing as some faint scratches are still visible on the brass under magnification and just because I could, I sized a pair of nickel plated cases with no indication of any issues. The final measurements did not show any real increase in the sized shells.

In hindsight I probably should have gotten the 400 as well to start off with, which more than likely would have done a better job of the “rough” clean up quicker leaving the 800 to final polish. I may get one of the 308 models to tune up my 30-30 and -06 dies.

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I'll try to remember that company. I've use bore brushes with bore solvent and bore mops with polishing compound before with good results. I even used a small engine cylinder hone to smooth up a rough operating powder measure once.

Thanks for that info. On a few occasions I have needed to open up a small ID a few thousandths and usually did the "split rod w/emery cloth" method but I believe next time I need a sizing die opened up or a cylinder cleaned up I'll check out BRM for a "real" tool...

I use fiber glass rods with sand paper wrapped around to open up sizing dies. To polish or clean up dies i use thick (not your dollar store ones) bamboo scewer and few cotton balls. Unroll cotton ball and roll around bamboo stick to make a large qtip. Cut it short and chuck it in your drill. Add your favorite polishing compound and go. I had to open up most of my Lee sizing dies to get correct size and few to increase size too. I use the same thing when cleaning up rusty dies just make sure you dont take off too much material when not needed and rotate your die so its all even.

All you need is to spin polish the die using 400 grit or finer silicon carbide wet or dry paper used wet with a light oil.
I have used that method to clean up maybe 50 used sizer dies.
It was common practice to polish parts with that technique in the machine shops I worked in for 7 years.
A sheet of paper costs only $.50 to $1.00.

I too have used the "split rod and emery cloth" method for many years (in both machine shop and automotive/heavy equipment shops). But even though it does work well, a regular "designed for" tool usually works better. I used flex hones on wheel cylinders, slave cylinders, and master cylinders, before it became "cheaper" to buy new replacements. On a couple occasions I used flex hones to clean up 2 cycle engine cylinders. Given a choice and had the time to wait for delivery, I'd opt for a flex hone for even my 30 cal sizing dies...

Brush Research also makes chamber hones for rifles and I can tell you these are a fine product. A few years ago we had a customer who owned an AR style rifle with an attitude. The rifle refused to allow fired brass to exit the chamber. Fired brass removal demanded a rod being inserted down the barrel to tap the fired brass away from the chamber. With the chamber empty I closely looked into the chamber and found it was coated with the same finish that was on the outside of the barrel. I called the manufacturer and they admitted that sometimes this happens when the muzzle and breech plugs they install don't keep the finishing chemicals out of the bore and chamber area. Rather than sending the rifle to them they offered to ship me a Flex Hone with instructions on how to polish the chamber. The hone has a long shaft to allow chamber polishing without having to disassemble the rifle. I followed the instructions and the rifle immediately functioned correctly. Since that time I have seen 3 or 4 more AR's with the same issue and I honed each of those to bring them into functional condition. When (IF) this hone wears down and no longer functions to clean these chambers I will buy another. They are simply too efficient to not have near the bench.

Honing a badly pitted straight brake or cylinder bore with a purpose built hone is the correct thing to do.
But I can polish out a FL die with 400 silicon carbide paper in about 2 to 3 minutes - much faster than trying to find an buy a store bought gadget that will not work any better than a $.25 piece of paper.

I am a user of steel resizing dies, both for handguns and rifles. When I get a new used set, I clean them with rubbing alcohol and them polish them. I chuck the die in the headstock of my lathe and with an oversize bore mop in the tail stock chuck. I wrap strips of paper shop towels around the brush and apply Mother's Mag Polish to the paper strips. I then run the mop/paper/metal polish in and out of the die turning in the head stock.

They have all come out with a mirror polish that leaves no scratch marks on the resized cases. Most of such scratch marks from from grit, dust and junk in the die and not from burrs or other hickies in the steel itself.

Of the dozens of dies I have polished all except one were scratching cases due to having sized gritty brass.

The one bad die was from Michigan and the interior was pretty rusty.
After being polished it had a bit orange peel texture from the rust.
However the cases sized in that die are as smooth and pretty as cases sized in any other die.


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. Most of such scratch marks from from grit, dust and junk in the die and not from burrs or other hickies in the steel itself.