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Help with metal selection please

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  • Help with metal selection please

    i thought the lathe purchasing would be the hard part, but getting the right tooling for said lathe is confusing as well !!!! now comes metal selection. im trying to make dies for swaging bullets. here is the size of most of the dies,od= .875 id=.355 length= 1 1/2 inches. the .355 hole will go all the way thru and will require punches to be made for base and nose forming. my question/s , do i have to use a tool steel and have parts sent off to b case hardened and tempered ? and hoping they come back to me somewhere close to the same size they left at ! or can i use another type of steel and sacrafice wear life (if it lasts a few years and i have to make another one then so be it). ive been doing some researching and have found as many recomendations as searches ive done (searched this site too) ive been told i could use 12L14 which machines very good but wear life is like nill , also could use 1117 or 4140 make part then use part dont have to have heat treated ?? read about kasinite (and seen on here some heated arguments) about its use !! i started into this to save money on buying these dies (very expensive) but this is quickly becoming rocket science to me ! thanks for any and all help in advance...bill btw i have bought some dies from a reputable company already and as far as i can tell (no experience at all) they have not had anything done to still look good no discoloration !!! thanks again !

  • #2
    I can't imagine swaging bullets with soft steel. I don't even like to use soft steel for cast bullet dies -- first time a bullet pics up a little grit (like from spent primer dust that is found around the reloading press) it scratches the die.

    But, if you want to try using soft steel, go ahead. Even if they don't work out, making them will be good practice.

    I'd suggest using O-1 and hardening the dies after machining. If you have an oxy-acetylene rig, that'll work for hardening small parts. Use the kitchen oven for tempering.

    Dimensions will shrink after the hardening process. Furthermore, they may continue to shrink for a few days or weeks. You'll have to fine tune the final dimensions by lapping.


    • #3
      You might ask over on the Benchrest forum. There are several guys that make bullets.



      • #4
        I have NO experience with reloading and such, but thought I might offer this suggestion.

        A lot of industries in the area have gone to using 4142 prehard for some of their medium duty tooling. It comes harder than mild steel, but not quite as hard as it would be if heat treated. You would get better service out of it than mild steel. It will scratch, however, but then again hardened steel also will under the right (abrasive) conditions.

        A2 and D2 were always the most common tool steels that we used in diemaking; D2 gets the hardest, while A2 was the all around general use. Both are air hardening, but have to be heat treated at 1750 for A2 and 1850 for D2. The i.d. of any holes in either tend to get bigger after heat treating (we reamed stuff about .0005" undersize and then honed to size after heat treat). Unless you are actually shearing steel, I would think these steels would be way more than what you need.

        If all you are doing is forming, I would think 4142 would be a good place to start. If you found you were wearing a bit more than what you thought, you could heat treat it and see what happens.