How do you polish a sizing die?

[bummer7]

I can use some help in fixing a problem i have with a sizing die. There are scratches inside the die that is causing case to have corresponding scratches when I resize cases.

Is there a way to polish out the scratches? Or do I need to buy a new sizing die?

 

[W.E.G.]

I bet the die is more dirty than scratched.

At least as it pertains to scratching the cartridge brass.

Take all the guts out of the die, and give it a good soaking in any oil.

Then chuck-up a bronze bore-brush in your drill, and whizz it out real good with the brush on the drill.

Clean up the guts and re-assemble.

See if it is still scratching the cartridge brass.

 

[jdsingleshot]

I have glued some fine wet-or-dry paper to a piece of wood that approaches the radius of the chamber and lightly scrubbed back and forth endwise around the entire surface. No chance of measurably altering the chamber by that means. My chamber quit scratching the brass--though it's true that the scratches were very light.

 

[Mark_Mark]

has to be a Lee die… only die I ever needed to polish…!

Fitz and felt tip from amazon

 

[Bazoo]

I have had occasion to need to polish a few dies. It depends on the brand and what you have to work with, what methods will be required. But on a basic level, if you spin the die and then use some very fine sandpaper wrapped around a dowel, it should alleviate your issue. I like 600 grit paper then move to 1000 grit, but anything similar will work. Then move to the finest scotchbrite pad you can get. Then flitz if you must. but I stop at scotchbrite.

For RCBS dies using 1/4x28 thread, its easy enough to use the threaded section as a mandrel. For dies with larger decapping rod threads, like a lyman. I make a mandrel out of a cap bolt that has a matching thread. Cut the head off and mount in a drill. But you need a 1/2" drill.

So what do you do if you don't have a suitable drill or drillpress? If you have any drill you can still make it work. First, get one of two things. Either double stick tape, or superglue. On your drill, turn your jaw teeth all the way in (open). Then either double stick tape, or use a drop of super glue to attach the die (top of die with guts removed) to the face of the chuck. Spin it and sand it, then remove it. Super glue actually works really well because a smack will remove it. It wont bond metal real strong. I've done it polish out H&I dies for my Lyman 450 sizer when a lathe wasn't available. It works like a charm.

 

[Yankee1986]

If your brass looks like mine in the thread below. All I did to remedy it was clean it with some alcohol on a paper towel and q-tips.

https://www.thehighroad.org/index.php?threads/lines-in-the-brass.905551/

 

[bummer7]

All good ideas and suggestions here. I already cleaned and scrubbed the die out really well. That helped somewhat as the scratches are not as obvious. FWIW, the scratches us in the body area. The neck area us okay.

The problem is I can still easily see three vertical lines inside the die. These same lines is what I see on the resized cases. Besides 600 to 800 grit sandpaper, i thought of using a wool mop and JB Bore Paste to polish the die. Is it posdible to wear away the die by polishing?

 

[cfullgraf]

I use a wood dowel with a slot cut in the top to hold the sand paper. Then use 400 grit progressing to 1000 grit wet/dry sand paper to polish out the die. I wrap a strip of sand paper around the dowel so that it is a loose fit in the die but mostly fills the space in the die. Experimentation will determine how long the sand paper strip needs to be.

Most frequently, I manually turn the dowel but it could be chucked in a drill.

At least with steel dies, I’m mostly cleaning out some debris that gets lodged in the die surface. Carbide dies, polishing is mostly cleaning out dirt and debris.

 

[AJC1]

All good ideas and suggestions here. I already cleaned and scrubbed the die out really well. That helped somewhat as the scratches are not as obvious. FWIW, the scratches us in the body area. The neck area us okay.

The problem is I can still easily see three vertical lines inside the die. These same lines is what I see on the resized cases. Besides 600 to 800 grit sandpaper, i thought of using a wool mop and JB Bore Paste to polish the die. Is it posdible to wear away the die by polishing?

A die is hardned and should resist your efforts. The problem is how deep you go. You can change critical dimensions.
The split dowel and paper method can help keep it concentric and not go crazy. What equipment do you have to work with?

 

[bummer7]

I have cordless drills and a drill press. I am thinking of jury-rigging a dowel and sandpaper to polish the inside or a mop and polish. But i am worried about altering the die's internal dimension if i am aggressive in polishing it.

 

[AJC1]

I have cordless drills and a drill press. I am thinking of jury-rigging a dowel and sandpaper to polish the inside or a mop and polish. But i am worried about altering the die's internal dimension if i am aggressive in polishing it.

If your using a fine paper lubricated it will take a lifetime but the quality will be superb. If you get aggressive it will be all over quickly, except the crying and regret.

 

[length_of_pull_1]

When I've had a die leave scratches like that I drop it in boiling water for several minutes then coat the thing with some oil making sure I wipe the heck out of the inside. Problem solved.

 

[bummer7]

When I've had a die leave scratches like that I drop it in boiling water for several minutes then coat the thing with some oil making sure I wipe the heck out of the inside. Problem solved.

I am intrigued. Please tell me how this works in getting the scratches out of the die?

 

[AJC1]

I am intrigued. Please tell me how this works in getting the scratches out of the die?

It's just cleaning. If it's clean it won't help.

 

[AJC1]

To remove the scratches in the brass only positive material is required to be removed. A die is not like a chamber with 50k psi pushing the brass outward. I would lap for 90seconds to two minutes, reclean and test.

 

[74man]

Go to the local auto parts store and get some valve lapping compound, 20^180 grit. Take a bore mop the same size and work the 180 first and then the 280 and that should remove the scratches!! Have even used that to open up tight cylinders on revolvers. Has a blackhawk and Ruger said that is what they do. Good Luck

 

[cfullgraf]

A die is hardned and should resist your efforts. The problem is how deep you go. You can change critical dimensions.
The split dowel and paper method can help keep it concentric and not go crazy. What equipment do you have to work with?

Well, cleaning a die with an abrasive compound or sanding sheet will affect the dimension's of the die. But, fortunately, the die is hardened and it takes lots of "cleaning" to make real effects on the specifications of the die.

My suggestion is to clean the die with some abrasive methods but don't go overboard with the method. Clean enough that the scratches in the cases are gone and stop there.

 

[Bazoo]

I've polished my 30-30 die several times and the brass sized shows no change in measurement. I figured out that if I reload brass that was fired but not cleaned internally, the carbon inside the neck will pull out of the case when the expander ball comes out. Those little bits of carbon then get in the die and cause scratches to both the die and then brass. I remedied this by converting to M die use for my rifle reloading. Another method would be to clean the inside of the necks much better. of course wet tumbling would do it, but I'm not set up for that yet.

 

[Kaldor]

I had an issue with galling on a sizing die. All it took for me was a soak in some BoreTech copper remover, you can see the blue from the brass coming out. I followed that with a piece of scotchbright on a dowel with toothpaste on it to ensure it was perfect. Probably could use something like Iosso or JB bore paste on a mop.

 

[Walkalong]

Nothing less than 600 grit.

 

[lightman]

Like the others have said, its more likely that your die has foreign matter stuck to it rather than being scratched. I would start with a shotgun bore brush with some bore solvent on it spun in a drill. Next I would use a shotgun bore mop with some polishing compound spun in a drill. Automotive polish will work fine.

 

[bummer7]

Like the others have said, its more likely that your die has foreign matter stuck to it rather than being scratched. I would start with a shotgun bore brush with some bore solvent on it spun in a drill. Next I would use a shotgun bore mop with some polishing compound spun in a drill. Automotive polish will work fine.

I wish it was foreign matter in the die wall. You can see three distinct lines in the die body. I'm going to try and polish the scratches out of the die. Failing this, i figure i will replace the body.

 

[Blue68f100]

I wish it was foreign matter in the die wall. You can see three distinct lines in the die body. I'm going to try and polish the scraches out of the die. Failing this, i figure i will replace the body.

I've a time have had to use a scraper to remove some embedded brass on a die once. These are common for machinist to have. Then I polished it out.

The split end of a dowel rod using a drill with 600grit sandpaper will normally remove any embedded debre. Once the sandpaper gets used up rotate some fresh surfaces into place. You can do this wet or dry your option. Wet will allow you to clean the paper off and continue. Once it's removed, start using finer grits up to 2000+ if you have it. This will but a high polish on the die. Run the drill at high speed. This will polish better. You don't have to worry about damaging the die. These are really hard to to scratch. Most mfg offer a polishing service if you can't get it out. Some do it free. If it can't be removed they will send you a new replacement die.

 

[bummer7]

Just a quick follow-up on this thread.

I want to thank everyone for their ideas, suggestions, and thoughts on this topic. Yesterday, I spent the afternoon working on the die. Using a dowel wrapped in 400 grit sandpaper attached to my drill press, I started off sanding the inside of the die for about 20 minutes. I stopped every few minutes to inspect the die. After sanding the insides, the scratches were gone. Then I used a bore mop and JB bore paste to polish the die's insides for the the next hour or so. I can tell you the inside of the die looks great! Super shiny and no scratches.

I did soak the die in a solvent tank for a few minutes, cleaned it, and then used it to size a few cases. I have to say resizing cases was a whole lot easier than before. Best of all, the sized cases do not show any scratches on them. Again, thank you all.
-s

 

[PWC]

You probably didn't remove much material, but now how do those cases work when fired?

Check for stretch and splits. If you have any cases left that are "pre-polish", measure against those run thru "post-polish". Probably neglegable but good to put in your load journal