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  • Testing hardening results

    I'm trying to hardening some shafting, and then determine results with file and hack saw by comparing to HSS. To my suprise I was able to file and saw HSS. Could see little difference between HSS and pre and post hardened material. Are there other ways to determine if hardness is achieved. Thanks for any help.

  • #2
    Hardness is relative. In other words, one material is always harder than another but what do you want to achieve? If you want a specific variable output then the best thing to do is acquire or find someone with a calibrated hardness tester. Otherwise, a "file" test is about as good any other low-tech method.

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    • #3
      What is the country of origin of the HSS? That could make a considerable difference.

      Commercially most hardness testing is conducted with a Rockwell hardness tester, something typically not found in a home shop. There are also portable AKA rebound hardness testers while not as accurate as the Rockwell type will get you in the ballpark. Travers Tool (and most likely other supply houses) also has a set of files designed to check the hardness of an item using the Rockwell C scale.

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      • #4
        Perhaps you could look at the Brinell scale and build some form of tester and calibrate against known samples.

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        • #5
          I have to question whether you were actually comparing to real HSS. Even the Chinese HSS I've used can't be filed or sawed with a hacksaw, including using Starrett blades. If what you were comparing to was in actuality HSS, I would suggest you got snookered when you bought it. Even carbon steel, hardened as they did in the old days when they forged lathe tools, would be difficult to cut with those methods.

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          • #6
            Hard Steel

            There is a dramatic difference between hard and non hard steel. A file or hacksaw will just skate over a real HSS lathe bit, hardly making a scratch.

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            • #7
              I was trying to make a single point dovetail cutter. Was comparing to endmill, HSS I thought. I have a porta band and I cut right through endmill. It suprised me, which is why I asked. I don't need any exact measure, just trying to see if my hardening procedure was sucessful. I heated to red heat/no magnetic attraction, then quenched in motor oil.

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              • #8
                I just tried another endmill, made in the UK and my porta band would not touch it. I guess that first endmill was made of cotton or something.

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                • #9
                  so where on on the end mill did you do this test? if the shank it could very well left soft; often only the business ends of cutting tools are heat treated

                  Originally posted by firbikrhd1
                  IEven carbon steel, hardened as they did in the old days when they forged lathe tools, would be difficult to cut with those methods.
                  carbon steel can be made just as hard or harder than hss....it just doesn't can't subjected to the same temperatures or it tempers.
                  .

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                  • #10
                    Yes, I tested on the setscrew notch. I had to go look again to make sure I was not crazy. The porta band made a clean cut halfway through, just as if it was unhardened drillrod. However, after trying test on various pieces of HSS, I now clearly see the difference. Thank you all for your help.

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                    • #11
                      See if you have a friend with one of these:

                      https://www.machineryhouse.com.au/Q520


                      Or just use Google:

                      http://www.google.com.au/#hl=en&outp...w=1920&bih=785

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                      • #12
                        Originally posted by lowcountrycamo
                        I heated to red heat/no magnetic attraction, then quenched in motor oil.
                        I assume you know that general hardenability and required quenching media vary widely beween different steels. Some steels cannot be hardened by simple heating and quenching, some require water or brine instead of oil to harden noticably. I'm not even talking about differences in critical temperatures, soaking time, etc.

                        Anyway, if you want, you can send me a sample of your hardened steel, and I'll measure its hardness for you.

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                        • #13
                          You said that you tried to harden "a shaft" ?? how long was this shaft? if more that a couple of inches, you may not have achieved a uniformly high temperature across its length... espically if you were just using a hand held torch flame.
                          Try cutting of a short length if your stock , about 1/2 inch, heat to a bright cherry red and plunge into water. If the stock is any kind of hardenable steel it should come out "glass hard", a file will just slide off of it.
                          Joe B

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                          • #14
                            Thanks to all for help. I will try all suggestions

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                            • #15
                              HSS is AIR quenched,NOT water or oil quenched. It requires an inert gas filled furnace to keep from decarbing badly on the surface. If you didn't get it at least hard well below the surface,perhaps you didn't get it hot enough,or somehow managed to decarb it all the way through.

                              I have made engraving chisels out of annealed M33 by just heating them blood red,forging them down to a tapered end(stuff was 3/8" square),and letting them air cool. The slight amount of surface decarb didn't matter,as I ground them down to the finished shapes anyway.

                              This was NOT the correct way to harden HSS,but for my purposes I made very tough,and plenty hard engraving (die sinker's chisels). I took them to the gunsmith's shop,and they began cutting down the soft tang of a file. I told them to keep going,and the graver kept cutting until 1/4" into the hardened area before the tip failed! By the way,I got a good tough HSS without drawing it afterward,as HSS is drawn at about 1000؛,which is about how hot I got mine.

                              I have no idea what you have done as red heat is no where as hot as they should have been heated,and I got mine hard.

                              I am wondering if you accidentally used some steel that was NOT HSS,and maybe wasn't even tool steel? It can happen.

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