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  • #16
    Originally posted by Fasturn View Post

    Wow you have machined some of the bad stuff too. Reading between the lines on this site, most have only machined the garden veriety. Kovar is one more like Inconnel high nickel , not nice to mill. I am retired, so brass , aluminum and delrin are what I enjoy to machine. Thanks for reading!
    Home shop machinists probably try to stay away from the exotics or newer even have to change work with them as you don't find inconel 718 bars from junk yard just like that.
    I have dabbled with inconel, aluminium bronze and hard-turning with cbn inserts to know the fun.

    Oxidized aluminium bronze infused with aluminum oxide particles? Yay, what a fun material to drill!
    Location: Helsinki, Finland, Europe

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    • #17
      Pure Tantalum is used in the creation of “ Trabecular Metal “ (Previously known as “Hedrocel”). A pure metal, open cell “foam”.
      The only way to cut TM for its intended use is with EDM. Conventional tooling smears closed the open cell structure and prevents proper innervation of bone into the implant. EDM, both sinker and wire, allows the open cell structure at the surface to remain available to growth of adjoining bone into the implant. It cuts great in the EDM but clogs up filters faster than steels.

      A couple spinal screws, a patella, a tibial tray cross section and a plug before becoming a screw. I made the 1st and 2nd human implanted Hedrocel Distal Femoral sections back in the ‘96>’99 time frame before the material was bought by Zimmer for their exclusive use. Raw material cost for one of those was $17,500.00. Not something you can take chances with.
      Click image for larger version

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      Illigitimi non Carborundum 😎
      9X49 Birmingham Mill, Reid Model 2C Grinder, 13x40 ENCO GH Lathe, 6X18 Craftsman lathe, Sherline CNC mill, Eastwood TIG200 AC/DC and lots of stuff from 30+ years in the trade and 15.5 in refinery unit operations. Now retired. El Paso, TX

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      • #18
        Originally posted by Fasturn View Post

        Probably would, the grind is important. You / me are showing our age : Rex AAA. Was the goto in the 70's Ask a youngster about Rex, and see the look you get?

        The Browning machine gun barrels were lined with Stellite for wear. Nasty stuff, but has its applications.
        Yeah, Rex was a Crucible Steel product. Sadly they are no more as a company, but the CPM steels are alive and well somehow.
        I wanna know how they lined those barrels with the stellite. Sintered perhaps? Electroplated? I doubt they did any machining after they were coated. Maybe die-sinker EDM after coating?Dunno but it must have been fantastically expensive. I've seen "parts kits" for the M1919 sell for thousands.
        25 miles north of Buffalo NY, USA

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        • #19
          Originally posted by nickel-city-fab View Post

          Yeah, Rex was a Crucible Steel product. Sadly they are no more as a company, but the CPM steels are alive and well somehow.
          I wanna know how they lined those barrels with the stellite. Sintered perhaps? Electroplated? I doubt they did any machining after they were coated. Maybe die-sinker EDM after coating?Dunno but it must have been fantastically expensive. I've seen "parts kits" for the M1919 sell for thousands.
          Stellite comes in many varieties and some are more machinable than others.

          This mentions hammer-forging steel sleeve over stellite liner or somehing like that:
          https://apps.dtic.mil/sti/pdfs/AD1008453.pdf
          (Hammer-forging is also commonly used for normal barrel rifling, SAKO barrels for example are hammer-forged around rifled mandrel)

          And another paper describes short stellite insert in the breech end of the barrel:
          https://apps.dtic.mil/sti/pdfs/AD0822736.pdf
          Location: Helsinki, Finland, Europe

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          • #20
            Originally posted by MattiJ View Post

            Stellite comes in many varieties and some are more machinable than others.
            Thanks for the education, I had no idea. The only "stellite" I had any experience with, is the type used for minig and rock crushing tools.
            25 miles north of Buffalo NY, USA

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            • #21
              Originally posted by Fasturn View Post

              Probably would, the grind is important. You / me are showing our age : Rex AAA. Was the goto in the 70's Ask a youngster about Rex, and see the look you get?
              Funny thing about it is, the AR Warner inserts are made out of T-15, and I've heard nothing but good about them. Conveniently enough, the inserts are made to standard dimensions just like carbide inserts, so they'll work in other company's holders, too.
              25 miles north of Buffalo NY, USA

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              • #22
                Originally posted by MattiJ View Post

                Stellite comes in many varieties and some are more machinable than others.

                This mentions hammer-forging steel sleeve over stellite liner or somehing like that:
                https://apps.dtic.mil/sti/pdfs/AD1008453.pdf
                (Hammer-forging is also commonly used for normal barrel rifling, SAKO barrels for example are hammer-forged around rifled mandrel)

                And another paper describes short stellite insert in the breech end of the barrel:
                https://apps.dtic.mil/sti/pdfs/AD0822736.pdf
                Wow....where did you get that info ?? Must be a Gun nut like the rest of us ,thanks.

                Nickel: : I have a 1919 simi and sold a part set for $ 1000. Last year. Bought it from SARCO for $ 250, 30 years back. Hey I made money.

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                • #23
                  Originally posted by Fasturn View Post

                  Wow....where did you get that info ?? Must be a Gun nut like the rest of us ,thanks.

                  Nickel: : I have a 1919 simi and sold a part set for $ 1000. Last year. Bought it from SARCO for $ 250, 30 years back. Hey I made money.
                  Coulda made a lot selling that here, my state (don't get caught)
                  (People's Democratically Elected Republic of New York)
                  has completely outlawed 50 BMG. You can't even get brass.
                  That stupid city is 450 miles from here
                  and they get laws passed that screw over everyone else.
                  25 miles north of Buffalo NY, USA

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                  • #24
                    Originally posted by Fasturn View Post

                    Wow....where did you get that info ?? Must be a Gun nut like the rest of us ,thanks.
                    "Evan method" aka google is surprisingly efficient. And having gunsmith as dad certainly helps also.
                    Location: Helsinki, Finland, Europe

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                    • #25
                      Originally posted by MattiJ View Post
                      "Evan method" aka google is surprisingly efficient. And having gunsmith as dad certainly helps also.
                      Ooo I'm envious. I have been dreaming of building a 7x57 for myself, among other things (I love the English double shotguns)
                      Lots of deer and geese here.
                      25 miles north of Buffalo NY, USA

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