Talking about Lee boolit sizers specifically, but anything similar will help.
What are the best ways (read - best results) to open up a sizer body to get a larger finished diameter?
What kind of surface finish is best, super fine polished, or less spectacular?
I'm talking going up a few thou from a standard size, .429-.432 or such. Who tried what, what works, what does not?
Thank you kindly.
If you ream it out you will need a larger piston or it will leak lube. They are normally .001 smaller than the die. For some reason all the 44 mag dies I've seen drop .431 or smaller. The sizer needs to be slick or the boolit will stick. I wish there were .433-434 dies available. I'd be happy with a four cavity mold that dropped .433 so I could pan lube without sizing. I have a mold that drops .436 and have to size .432. My gun has .433 throats. I could powder coat but I'm too old to start over.
Last edited by 45DUDE; 02-29-2024 at 12:43 AM.
I figured the best surface finish you can muster is best.
Do you think the piston needs to be that close of a fit? Fairly simple to spin one up on the lathe, but I don't see the need unless grossly undersized.
The standard way to open up a Lee push through sizing die is to take a piece of wooden dowel, make a split in one end, then insert a piece of sandpaper into the slit. Chuck up the dowel in an electric hand drill and use this contraption as a lap to hone out the size of the die. Start with 120 grit wet/dry sandpaper (for metal, not emery for wood) and check the internal diameter often. You want to hog out around .003", but most folks just want to open the diameter by around .001" or so. For removing that much metal I'd use several strips of 120 grit. Make sure to push a boolit through every now and then to check the die's diameter. When you are getting close to the diameter that you want (just over half a thousandth or so) switch to finer grit abrasives to polish the interior of the die. Usually a couple of passes with 220 grit, followed by a couple of more with 320 grit will do the job. You could go to 400 grit if you want, but 320 grit will give a nice smooth surface. I usually "hone" those dies dry, but you could use some oil if you want. Also, wipe out the inside of the die with a rag or some paper towel before pushing a bullet through to check your size, or the grit will get stuck in the bullet.
Saw your new comment about the post after I was typing. You want the post to be a close fit, not just for pushing the bullet through the die, but also for when you use a push through die for crimping on gas checks. I would think that if the post had .002" to .003" of clearance it should be fine, but if the post is too small it might start trying to squeeze lead (or gas check) around itself and make for a lousy bullet base.
Last edited by 405grain; 02-29-2024 at 12:21 AM.
I was planning a similar approach. Appreciate the input! Those numbers were just thrown out for an example, I have a few dies that I want to open up a little. My initial thought was chucking them in the lathe and running a wet or dry lap through like you stated. I have paper running all the way up to 2500 grit laying around here somewhere, ha ha. Didn't want to go wild if 400 would suffice.
405grain
I'm talking regular sizing. If I were installing checks, I'd definitely make a custom size post to fit the base! Thanks again ����
The op stated Lee sizing does. There is no lube associated with Lee sizing does other than liquid Alox. Alox is applied before and after sizing. Not through a die.Originally Posted by 45DUDE
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Or pan lubing with conventional lube...
As for odd size dies, Lee has been very helpful in making custom push-through dies for me. First time I approached them for a special size, their response was "When do you want it?"
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Live and learn. Thanks for the update. Sounds kind of slow. I may get one and hog it out to .434 if the steel is soft enough. I may be better off swapping for a gun with smaller throats.
Last edited by 45DUDE; 02-29-2024 at 04:22 AM.
I used a thru hole lap and lapping compound with my battery powered drill to open up the neck of a 40-65 sizing die. You will need a few minus gauge pins also to measure your progress. I started with 280 and finished up with 400 grit.
Last edited by steveu; 03-18-2024 at 05:26 PM.
Lee sizers that I have used are soft, so get a handful of boolits and check often. 120 grit will cut one pretty quick.
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That hasn't been my experience with Lee push through sizers, they have been as hard as heck.
I anneal mine to soften them before opening them up.
A split wood lap and fine emery paper Will do the job.I dont normally go to 120 grit I start with 240-280 and work to 600 then a strip of flannel to fit snug with flitz or shimichrome on it to finish.Get with in a couple ten thousandths for the pastes. they wont remove much but will give a very smooth surface. I use a strip around 2" wide low rpms and feed it back and forth fast. the polish lines look like figure 8s inside. Check often by pushing a couple bullets thru the die and measuring. Measure at 2-3 points to make sure your not egg shaping the die. When you get with in .0005 go to the flitz or shimichrome. Yellow diamond dust also works well here. Red Rouge on the flannel will also give a great finish. You want the wraps of abrasive to be running snug in the bore to tight and its hard to maintain movement to loose and it dosnt cut even. Use a light oil to keep paper clean in a pinch dish soap works well. When you go to the pastes once you start only add oil or soap try not to add more paste. As you polish the pastes abrasives break down to finer and finer grits improving polish adding more starts over on this process.
You will feel the abrasives cut and the tension lighten as they remove material. The light oil soap will keep the papers from loading up so they will cut more evenly. 240-280 then 320 400 and 600.
Better is to make a wood, lead, or brass lap with a screw in the end and true lapping compounds. Adjust to snug in the die and add compound. The compound will embed in the softer material and cut the die, this is easier to start in the die and cuts a much rounder bore.
Coat a bullet in fine lapping compound and send it through a few times clean it out then size a fresh bullet. Rinse and repeat until you're there.
Great info everybody, much appreciated!
Country gent, thank you for the well laid out, real world data. That's what I'm looking for! I'll post results when the experimental die sets get here.
Little update, just in case anyone is actually paying attention to this thread... Both of the LEE push through sizers I was waiting on, are here in the lab. I'll be checking the nominal sizes and deciding which one is getting opened up. More to follow.
I have done this multiple times.
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It's worth pointing out that Buffalo Arms sells custom lubesizer dies. I bought a .433" die from them years ago and have been very happy with it, and the price was very good too.
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