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Quench oil

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  • Quench oil

    I have some special O-6 graphited tool steel on order. Anong other things I need to make some replacement dies for my Roper Whitney hand punch. This is an oil quenching tool steel. It is heat treated at 800C. Any recommendations for an oil to use for quenching?
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  • #2


    • #3
      Evan, are you sure O-6 is up to the application. Granted it will get hard enough but will it hold an edge. L-6 might be a better solution. Made my shim punch out of it over 20 years ago and I haven't had to resharpen it yet.
      Forty plus years and I still have ten toes, ten fingers and both eyes. I must be doing something right.


      • #4

        Punches and dies as well as plug guages etc are what O-6 is recommended for. It's the machinability I like. It is rated at 125% machinability.

        See here:

        and here:
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        • #5
          Evan, I have a little bit of experience in this area. I've made small parts in the past out of 0-1, and had moderate success quenching these with automotive oils. I say moderate because the oil does not always quench the part quickly enough, so oftentimes you do not achieve the desired hardness.

          A proper quenching oil has a much higher flashpoint in any automotive fluids, and is usually low in viscosity so the convection carries it quickly around the part. Quenching oil is not terribly expensive, and is readily available from McMaster-Carr, whose web site is when you go there, search for quenching oil and you'll find it quickly. It's about eight dollars US for 1 gallon and around $36 for 5 gallons. They sell a standard quenching oil, which claims a 28 second quench time, as well as a high-speed oil which claims a 10 second quench time.

          Hopefully McMaster ships to Canada.

          Good luck


          • #6
            I avoid ordering from the US unless there is no alternative, especially for low cost items. By the time I got an $8 gallon of oil here from McMaster Carr it would cost $40.

            What about 10 weight straight mineral oil?
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            • #7
              I think you're on the right track with about a #10 oil, something fairly thin. Maybe some plain hydraulic oil.

              Try to make a living, not a killing. -- Utah Phillips
              Don't believe everything you know. -- Bumper sticker
              Everybody is ignorant, only on different subjects. -- Will Rogers
              There are lots of people who mistake their imagination for their memory. - Josh Billings
              Law of Logical Argument - Anything is possible if you don't know what you are talking about.
              Don't own anything you have to feed or paint. - Hood River Blackie


              • #8
                A spec sheet on my O-1 merely states to use a "thin warm quenching oil" heated to 125 degrees F.
                On the various knife forums I visit there are a wide range of opinions as to what's the best quenching medium.
                Along the line of things you might be able to get locally, one gentleman stated he used veterinary grade mineral oil (don't know how that differs from your straight mineral oil you mentioned)and had good results with it. Olive oil is mentioned on this site regarding O-6:

                - Jim


                • #9
                  I do plenty of quenching,you don't need anything special,we use hydrualic oil at work,its thin,cheap and has a high flash point.The only requirement it that it be free from moisture,in other words nice,clean oil.

                  I have on ocassion needed a higher flash point oil,solution-2-cycle,Wal-mart $9.28 a gallon.

                  One other consideration is heat build up,it doesn't take too many parts to heat the oil volume,anything above 150* and its time to quit.
                  I just need one more tool,just one!


                  • #10
                    I use used automatic transmission oil (fluid). It's free (when you change your own), mineral oil based and high flash point.

                    I don't think the steel will care about the friction additives.

                    (Trans fluid will handle 350*F+ all day long without breaking down).

                    [This message has been edited by CCWKen (edited 05-07-2004).]


                    • #11
                      ATF or 10wt hydraulic fluid. Have plenty in your quenching bucket.
                      Location: North Central Texas


                      • #12
                        I used a combination of oils and such for my quench. TYhe basic formula is 2 parts 30w motor oil, 2 parts Olive oil and 1 part ATF.

                        This works great for HT processing on O-1 and some other steels that I made knife blades from.

                        Hope this helps,



                        • #13
                          I did consider ATF. I guess I'll try that. Thanks guys.
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                          • #14
                            This thread is probably about used up but I'll throw in my two cents. In Kozo Hiraoka's book on building the Pennsy A3 locomotive he advises using regular cooking oil as a quench oil. I've never tried it so can't say how it does.


                            • #15
                              Hmmm... The O-6 retains oil in the graphite. Pulls it in as it cools. Tools that smell like french fries....
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