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Thread: Fun with a hardness tester
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19th Aug 2012, 10:59 AM #1Pink 10EE owner
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Fun with a hardness tester
Greg recently sold me his hardness tester..... It is a Japanese made unit from 1974..
It measures Rockwell C and Rockwell B..
Here are some results from various things around the shop... All resuts are in HRC scale
CTC Tools HSS..various sizes 58
RIMET 1/4 square M42 HSS 65
Bohler 1/2" square HSS 65
Ridgid 1-2" universal pipe die HSS 60
Chinese HSS 4mm die 63
Old P&N die locally made 56
4140 round bar 1/2" 24
4140 round bar heated to orange colour and quenched in water no tempering 57
4140 bar heated to orange colour but 8mm away from the last test where the bar was cooler when quenched 23 (this one amazed me and it showed how critical the correct temperature for hardening is.. If it does not get hot enough, nothing changes)
Au made Sidchrome spanner 45
Teng tools spanner 44
generic spanner that comes with new cars 38
allen key 50
screwdriver 38
Quite an interesting array of hardnesses there...Gold, the colour of choice for the discerning person.
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19th Aug 2012, 12:44 PM #2
You didn't try the toaster and the butter knife.
Interesting list non the less.anne-maria.
Tea Lady
(White with none)
Follow my little workshop/gallery on facebook. things of clay and wood.
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19th Aug 2012, 04:05 PM #3Pink 10EE owner
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Well I did some Victorinox steak knives.... 53HRC and a NSK bearing.... 59HRC
Gold, the colour of choice for the discerning person.
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19th Aug 2012, 06:38 PM #4Most Valued Member
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Hi RC,
Interesting post, hardening is something that I will need to learn in the future.
Could you oil quench a sample of hot rolled steel and test it ?
Also do you have an oven and have you noted what sort and size of dimensional change's you get after heat treating ?
I seem to remember (years ago) that when we made shafts for hydraulic pumps motors and cylinders we did a final grind of .015' or .020 when they returned from the heat treater's.
thanks, john
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19th Aug 2012, 07:09 PM #5I break stuff...
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Those results I find quite interesting... I remember a thread some time ago where I commented that HSS (on the lathe) for me just didn't last on any steels, especially on interrupted cuts. The suggestion was made that CTC's HSS (all I have) tended to be a bit soft, and other brands held an edge much better - your testing would seem to prove that point!
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19th Aug 2012, 07:52 PM #6Pink 10EE owner
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Mild steel hot rolled will not harden very much if heated and quenched, as it is only carbon in steel that allows steel to harden..... All the other alloys that are added only serve to change the characteristics of the quenching and tempering process...
I do have an oven but have not yet got around to using it...Other then testing it... It is only a small one...
yes hardness would have a bit to do with it, but the elements added to HSS would probably probably be more important.... Take a file for example, you could use it as a lathe tool as it is hard, very hard, but it simply does not last as a cutting tool, as the temperature at the tool tip is quite hot due to the cutting friction and at elevated temperatures steel becomes softer, but elements like Tungsten and Molybdenum allow steel to be raised to higher temperatures before the tempering process begins..Gold, the colour of choice for the discerning person.
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