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Looking for Ideas on Case Forming

5mmgunguy5mmgunguy Member Posts: 3,853
edited September 2007 in Ask the Experts
How tough would it be to make case forming dies? I would think the case hardening would be the most difficult. How important would it be to case harden? If you didn't case harden the steel would still be much harder than brass and should last a long time without case hardening.

Comments

  • Tailgunner1954Tailgunner1954 Member Posts: 7,815
    edited November -1
    Most dies are made from a stainless steel that's been through hardened, after reaming, to about RC45 or from a leaded steel that's left in it's natural (unhardened) state. At least that's what Troy Newlon www.newlonprecision.com told me when I ordered a blank from him.
  • JKJK Member Posts: 223 ✭✭✭
    edited November -1
    5m/m,
    I don't know your level of expertise or if you are doing the job yourself or not. Tailgunner states (which is correct) that the steel has to be RC 45. You can't machine with a tool much harder than that with any degree of accuracy. RC 40/45 is about the norm. Case hardening after the die is to dimension has a tendency to warp to a certain degree which you can't do anything about. That you have to live with. Once it's cased you can no longer use any tool on it such as a reamer. You can have it ground but the cost is prohibitive. Cheapest way around this would be to make it very slightly undersized. All this can be done on a GOOD lathe without the use of ANY reamers. When it's done to your satisfaction you can have it flash chromed to approx .0002/.0005 build up on a surface, (more if you have a greater degree of accuracy for the undersizing). Then if you wish you can lap the dimensions with diamond dust. The diamond will not impregnate the chrome when you clean it off. This will produce a very hard and durable and smooth finish, (V-6/15) and the surface will last for years.
  • 5mmgunguy5mmgunguy Member Posts: 3,853
    edited November -1
    Thanks for the great info so far. I am a fair machinist, at least I haven't gotten any complains. But new to case forming. I would assume while forming brass I would have to do it in steps, each one sucessively smaller. How much should I make each step? .025? Also the brass I would assume will work harden and grow in thickness. Any way to calculate the thickness growth based off original wall thinkness?
  • JKJK Member Posts: 223 ✭✭✭
    edited November -1
    The dies I can tell you about with no problems other than if you are drastically forming or not. You will need more than one if this is the case. About dimensions, I'm sure there are a very many on the forum that will take it from there. The only forming I did was minimal, dies, many.
  • JOELBLACKJOELBLACK Member Posts: 30 ✭✭
    edited November -1
    I form cases by judicious use of measurements from CoW and handgun carbide sizing dies. Simply neck up or down a case with the same base diameter and sufficient length. Push the shoulder back and trim to where it will enter the chamber. load with 5grs of Bullseye and fill with Cream of Wheat. Fire and trim again.
  • Tailgunner1954Tailgunner1954 Member Posts: 7,815
    edited November -1
    5mm
    Pick up a copy of "The Handloader's Manual Of Cartridge Conversions" by John J. Donnelly. He covers a lot of "conversion" techniques, tools and procedures.
  • p3skykingp3skyking Member Posts: 25,750
    edited November -1
    quote:Originally posted by Tailgunner1954
    5mm
    Pick up a copy of "The Handloader's Manual Of Cartridge Conversions" by John J. Donnelly. He covers a lot of "conversion" techniques, tools and procedures.


    Tailgunner beat me to it! This is the modern bible of cartridge conversions. You can make any cartridge without much need for forming dies. With it, and Cartridges of the World, I have created several obsolete cartridges, like the 11mm Murata and 8mm Nambu, and put weapons back on the firing line.
    I also aquired a Unimat miniature lathe to turn down rims and cut new extractor grooves. Being a machinist, your skill could be used to make lead bullet molds of obsolete cartridges which I had to have custom made.

    Have fun![:D]
  • v35v35 Member Posts: 13,200
    edited November -1
    I've made case forming dies from low carbon steel and left them soft
    for limited use of a few hundred cases. It worked and the dies haven't worn out.
    To avoid warping in the case hardening, anneal or stress relieve the metal before machining.
  • nononsensenononsense Member, Moderator Posts: 10,648 ******
    edited November -1
    5mmgunguy,

    Technically, in the manufacturing sense and for extreme longevity, dies are normally hardened or plated with one recipe or another. I have mentioned before that E-Nickel works for me.

    On the other hand, as v35 points out, for some average needs or experimentation, mild steels up to A2 will work just fine even for fairly long runs, at least for us non-manufacturers. I've used 8620 or some variation because it's readily available and easily machined. It can be case hardened if you want. When polished, these dies are very serviceable.

    Don't forget that you do not have to make threaded dies for your case forming experiments. Dies used with an arbor press are sometime faster and easier to make and will produce very accurate cases, just ask a benchrest shooter! I have dozens of sets of these types of dies used for cartridge conversions for experiments and making wildcat cases that are not available for general retail. If you take a look at the Wilson Die page, there are some drawings you can use for ideas if you want.

    http://lewilson.com/

    Threaded die blanks:

    http://newlonprecision.com/

    Just for reinforcement, you should look at the cartridge conversion books because they have an incredible amount of information in them and they are just plain fun to read. Both books that I have are filled with cartridge case drawings. Dave Kiff has a book of chamber drawing out and it is useful as well.

    Best.
  • 5mmgunguy5mmgunguy Member Posts: 3,853
    edited November -1
    Thanks to everyone for all the great and useful advice. I will let you know how it works!!
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