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Different grades of HSS tool?

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  • Different grades of HSS tool?

    I received a box full of tooling but there's a nyriad of different makes and grades, some is HSS others are cobalt. There doesn't seem to be any convention for identifying the different grades. I've given a few a lick with the grinder, and many seem to grind quite readily yet others are slow to grind, and some are very hard.

    How do I sort-out what's good and what's not so good, and when to use one grade over another? I don't think I need to keep it all, if I lived a hundred years I'd never wear them all down with what little I do.

    Here is some of the selection, some like eclipse H5 I have quite a few of, others I have singly or very few:

    Peter - novice home machinist, modern motorcycle enthusiast.

    Denford Viceroy 280 Synchro (11 x 24)
    Herbert 0V adapted to R8 by 'Sir John'.
    Monarch 10EE 1942

  • #2
    There's no convention in labeling carbide insert grades either. It's gotten a little bit easier of late as many of the carbide makers have gone to a 4-digit system. In those, the second pair of digits usually indicated toughness vs. wear resistance. A "10" or "15" would suggest hardness and wear resistance, a "30" or "45" would be tougher and more chip-resistant (but wear faster.)

    They've also started giving some indication of material classes a grade might be intended for by incorporating "P" (steels), "M" (Stainless steels), "S" (superalloys), "N" (non-ferrous) and others into the grade designations.

    HSS makers seem to prefer cool names that mean little.

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    • #3
      HSS types

      http://www.diamondbladeselect.com/kn...ade-standards/

      http://www.google.com.au/#hl=en&sour...25f3317bd5ad27

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      • #4
        Thanks tiffie - a bit of useful info there. I guess I'll just have to use each type and see how it performs on different materials. Keen to try that stellite stuff to see if it holds-up to machining 316 better than normal HSS but it glazes my grinder wheel in very short order.
        Peter - novice home machinist, modern motorcycle enthusiast.

        Denford Viceroy 280 Synchro (11 x 24)
        Herbert 0V adapted to R8 by 'Sir John'.
        Monarch 10EE 1942

        Comment


        • #5
          You need a better wheel for the Stellites and Cobalt bearing tools. Others will tell you which. The ones I have mounted don't do much to them, either. Have to change them.

          Take a magnet to those tools. Those that are non-mag are apt to be high cobalt, Stellite, or another brand of better HSS.

          Stellite will have a notch ground into the top face of the tool. That being up is the strongest orientation of the bit when you grind it.

          As they have little to no Fe in the alloy, I assume diamond is safe to use on them.

          Cheers,

          George

          Comment


          • #6
            Stellite

            Diamond wheel it is George.

            Its berluddie tuff stuff that "Stellite". It was the tool of choice for "hard to machine" stuff when there was not the selection of TC and the like tools that we have today.

            There are several grades of it:
            http://en.wikipedia.org/wiki/Stellite

            http://en.wikipedia.org/w/index.php?...t=Search&ns0=1

            http://en.wikipedia.org/w/index.php?...t=Search&ns0=1

            http://www.google.com.au/#hl=en&sour...25f3317bd5ad27

            http://www.google.com.au/#hl=en&q=st...25f3317bd5ad27

            http://www.google.com.au/#hl=en&q=st...25f3317bd5ad27

            We used to drill files and the like with it. Sharpen to a triangular/three-sided pyramid, relieve the triangular faces/facets, start the drill -the more speed and power the better, lean on the drill and don't ease up, and it will heat the job/file and melt/go right through it.

            Works well for hard-facing as well.

            It isn't something that can be ground or used in many smaller/HSM shops.

            I've been promising myself for quite a while that I must make an effort to get and try some - even if just "for old times sake".

            I was drilling a job not so long ago that was work-hardening - badly - and Stellite would have been just the job for it.

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            • #7
              Tiffie,
              What does it cost to send an ounce or 2 to NZ? They do me no special good, I do not machine for a living, I am disabled and retired.

              I have various sizes, name the square that you use in your machine. If it is just nominal postage, gratis. If it is bucks, I will ask for fiduciary help.

              This is not an open offer. I would probably get more scrapping it than I could get from the replies I have gotten here regarding Stellites. Basically, They're junk steel, the cheapest carbide is better, What WE use is better, Chinee scrap is better, etc., etc.

              But, then, I am posting on a board that is peopled by experts who know way more than I do.

              Ah, well.

              Cheers,

              George

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              • #8
                Just keep well in mind that grinding cobalt is a hazardous business. Cobalt is readily absorbed into the blood if ingested or breathed because it is next to iron on the periodic table. The mechanism in the body that absorbs iron will also absorb cobalt. Cobalt is very toxic. Also, if you are working with cobalt stay well away from food or drink that contains vitamin C. Vitamin C increases the absorption of both iron and cobalt by over 4 times.
                Free software for calculating bolt circles and similar: Click Here

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                • #9
                  Stellite

                  I have a few 0.25" Stellite tool bits. I used them on my 13" South Bend with a forged toolholder designed for HSS. The tool holder had the 15* back rake built in. The tool angles recommended for Stellite are considerably less than those for HSS. With this cobbled set up I was able to turn hardened axles. The swarf came off in an orange ribbon. The turned surface was equal to that achieved with carbide tooling on more powerful, faster lathes. As I recall I ground the bit on my bench grinder. It was slow going and the wheel required frequent dressing to remove the glaze. I honed the bit on some Japanese water stones to a mirror finish. Hand honing the bits probably caused some rounding of the cutting edge. I had a 2HP 3PH motor powering the lathe via a home made rotary converter. The lathe used every bit of the available power to pull the cut. I think I was running about 150'/min.
                  Larry on Lake Superior

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                  • #10
                    Originally posted by Evan
                    Just keep well in mind that grinding cobalt is a hazardous business. Cobalt is readily absorbed into the blood if ingested or breathed because it is next to iron on the periodic table. The mechanism in the body that absorbs iron will also absorb cobalt. Cobalt is very toxic. Also, if you are working with cobalt stay well away from food or drink that contains vitamin C. Vitamin C increases the absorption of both iron and cobalt by over 4 times.
                    Intresting. I guess thats a good reason for me to stick with my cheap chinese HSS.. j/k

                    But seriously, how dangerious is it?
                    Should one only grind it outside? With a mask? Is my driveway full of cobalt dust gonna be a problem?
                    Play Brutal Nature, Black Moons free to play highly realistic voxel sandbox game.

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                    • #11
                      From OSHA:


                      Inhalation of cobalt metal fume and dust may cause interstitial fibrosis, interstitial pneumonitis, myocardial and thyroid disorders, and sensitization of the respiratory tract and skin. Chronic cobalt poisoning may also produce polycythemia and hyperplasia of the bone marrow. Among 12 workers engaged in the manufacture or grinding of tungsten carbide tools (cobalt is used as a binder for tungsten carbide crystals), who developed interstitial lung disease, there were eight fatalities.


                      Exposure Limits

                      The current Occupational Safety and Health Administration (OSHA) permissible exposure limit (PEL) for cobalt metal, dust, and fume (as Co) is 0.1 milligram per cubic meter (mg/m(3)) of air as an 8-hour time-weighted average (TWA) concentration [29 CFR 1910.1000, Table Z-1].

                      Signs and symptoms of exposure

                      Acute exposure: Acute exposure to cobalt metal, dust, and fume is characterized by irritation of the eyes and, to a lesser extent, irritation of the skin. In sensitized individuals, exposure causes an asthma-like attack, with wheezing, bronchospasm, and dyspnea Ingestion of cobalt may cause nausea, vomiting, diarrhea, and a sensation of hotness.


                      Chronic exposure: Chronic exposure to cobalt metal, dust, or fume may cause respiratory or dermatologic signs and symptoms. Following skin sensitization, contact with cobalt causes eruptions of dermatitis in creases and on frictional surfaces of the arms, legs, and neck. Following sensitization of the respiratory system, cobalt exposure causes an obstructive lung disease with wheezing, cough, and shortness of breath. Chronic respiratory exposure results in reduced lung function, increased fibrotic changes on chest X-ray, production of scanty mucoid sputum, and shortness of breath. Chronic cobalt poisoning may cause polycythemia, hyperplasia of the bone marrow and thyroid gland, pericardial effusion, and damage to the alpha cells of the pancreas.


                      http://www.osha.gov/SLTC/etools/sawmills/cobalt.html
                      Free software for calculating bolt circles and similar: Click Here

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