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Thread: Genuine Brinell Hardness Tester, Cheap

  1. #21
    Boolit Master
    WilliamDahl's Avatar
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    Quote Originally Posted by Cane_man View Post
    simpler yet, just put the ball bearing between a pure ingot of lead and your sample, make an indentation with a hammer or vice, then measure both diameter indetations... take the ratio of the pure lead indent to the sample indent and multiply this by 5... or use a pencil lead test ...
    The pencil lead test is an approximation, not a scientific measurement. It is probably the most portable of all the methods though...

    The hammer test requires a reference source of lead. I am not sure whether it results in values that are just a good approximation or whether the mathematics are exact.
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  2. #22
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    Quote Originally Posted by Markbo View Post
    All this time & effort and what ifs and how abouts really makes me appreciate my simple Lee tester.
    From what I've read, a lot of us old farts with old eyes don't particularly like the pocket microscope that comes with the Lee Hardness Tester.
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  3. #23
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    I just got through trying this method (i.e. arbor press, ball bearing, computer scanner, and GIMP). It is definitely easy to read. My scanner only goes to 600 dpi though, so the indenter diameter in inches = pixels / 600. I'm getting a BHN of 26.15 on the water quenched unknown alloy bullets that I had recently cast. That seems a bit high, so I'm going to have to review my procedures a bit. I'm hanging two 2-liter soda bottles filled with water from the end of the arm on the arbor press. They weight 2.124 and 2.138 kg each and with the 20:1 ratio on the arbor press, that should about 187.92 lbs. Probably going to actually have to put a scale under the arbor press arm to verify the force that is being applied to the indenter ball. Probably should also verify that the ball is the diameter that I think it is also...
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  4. #24
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    It would appear that my estimate of the force being produced was not right. Maybe because I did not have the string that was looped over the handle all the way out. The force (according to a digital bathroom type weight scale) was 148.5 lbs. That works out to a BHN of 21.87 which is entirely plausible.
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  5. #25
    Quote Originally Posted by grumman581 View Post
    I just got through trying this method (i.e. arbor press, ball bearing, computer scanner, and GIMP). It is definitely easy to read. My scanner only goes to 600 dpi though, so the indenter diameter in inches = pixels / 600. I'm getting a BHN of 26.15 on the water quenched unknown alloy bullets that I had recently cast. That seems a bit high, so I'm going to have to review my procedures a bit. I'm hanging two 2-liter soda bottles filled with water from the end of the arm on the arbor press. They weight 2.124 and 2.138 kg each and with the 20:1 ratio on the arbor press, that should about 187.92 lbs. Probably going to actually have to put a scale under the arbor press arm to verify the force that is being applied to the indenter ball. Probably should also verify that the ball is the diameter that I think it is also...
    Don't rely on the scanner to be exact at 600/inch. Scan a small strip of flashing or shim stock that is approximately 0.1" wide and verify with a caliper.

  6. #26
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    Quote Originally Posted by johnnybar View Post
    Don't rely on the scanner to be exact at 600/inch. Scan a small strip of flashing or shim stock that is approximately 0.1" wide and verify with a caliper.
    Why that vs perhaps something like the diameter of a penny?
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  7. #27
    Boolit Master Markbo's Avatar
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    Quote Originally Posted by WilliamDahl View Post
    From what I've read, a lot of us old farts with old eyes don't particularly like the pocket microscope that comes with the Lee Hardness Tester.
    My eyesight sure isn't great but it works well enough

  8. #28
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    Well, I just scanned in a penny on my scanner at 600 dpi. It came to 449 pixels and if I looked at it just right, I could definitely say 450 pixels which is exactly 3/4" (the diameter of a penny according to the government's web site). So makes it entirely plausible that the scanner can be used to determine the width of the indentation.
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  9. #29
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    Hmm?

    Seems to me that the price of ONE MOLD gets you a Cabine Tree hardness tester and allows you to avoid all that Wile E. Coyote B.S., but that's just me. . .
    WWJMBD?

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  10. #30
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    Quote Originally Posted by Bigslug View Post
    Hmm?

    Seems to me that the price of ONE MOLD gets you a Cabine Tree hardness tester and allows you to avoid all that Wile E. Coyote B.S., but that's just me. . .
    And buying commercial ammo would save us all the "W.E.C. BS" that we go through to smelt, cast, and reload our own... But what would be the fun in that? I already had an arbor press, so the only thing I really spent on making my hardness testing system was an $8 analog bathroom scale since the digital one that I had does not work well with fluctuating weights (which happens when you try to hold the weight by hand instead of just hanging a fixed weight on the end of the arbor press's lever arm. The computer had been retired a couple of years ago -- same with the scanner. They were just collecting dust in a closet. Instead of looking in a small eyepiece and trying to measure the size of the indentation, I get to look at a image on a screen where the indentation is around 6" or so in apparent diameter. Don't know about you, but my old eyes like that idea.

    Besides, as an engineer, I like the idea of creating my own measurement tool and seeing what goes into it. I'm thinking that it would be possible to make it even simpler if you were to use a 2nd-order lever based system to replace the arbor press. I'm thinking 3" between the fulcrum and the indenter and 30" between the indenter and the end of the lever arm so that it will have a 10X or so multiplicative force. That would mean that you would only have to hang a 16 lb weight on the end to get 160 lbs on the indenter ball (good for 1/4" ball) or less weight with a 5/32" ball. Of course, that's not counting the weight of the lever, so it would need to be adjusted slightly.
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  11. #31
    Boolit Master Markbo's Avatar
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    Quote Originally Posted by grumman581 View Post
    ... Besides, as an engineer....
    Well that explains everything!

  12. #32
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    Bumping an old thread.
    I just obtained some old diving weights and did my own homemade test on hardness. I took apart one of my son's skateboard bearings and got 7ct 5/32" (3.95mm) bearings out of the deal. I was simply lucky. More luck is that I weigh 230 lbs. I placed the 10lb chunk of alloy on 4 bearings on the cement floor and stood on it for 30 seconds.
    I got 4 indentations to measure. Grabbed a 10x loop and micrometers. Average hole was 0.071". Voila.

  13. #33
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    Still using the redneck version and saving for the Cabin Tree.....someday.
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  14. #34
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    Quote Originally Posted by HenryC460 View Post
    The test calls for pressing a 10 mm ball into the lead for 30 seconds with a force of 220 lb. (a 100 kg weight).

    Then enter in the diameter of the ball, the diameter of the dent, and the weight of the weight you used into the familiar Brinell Hardness Number Formula. Or use this online calculator:

    http://www.easycalculation.com/physi...l-hardness.php

    The cheap tester I use consists of a C-clamp with an epoxided on 1/4" washer and an epoxied on 3/8" ball bearing on the top jaw of the clamp. The epoxy and washer helps keep the ball from rolling and shooting out to the side sometimes.

    The lead to be tested sits on a 4" x 4" piece of 1/4" steel plate on top of a bathroom scale near the edge of a table or bench. Whatever the scale reads with the steel plate and the lead sitting on it, the bottom jaw of the C-clamp is hooked under the edge of the bench, and the ball is cranked down into the lead until the scale reads 220 lb. more than what you started with. One Mississippi, two Mississipi, three Mississippi, ...

    After 30 seconds, uncrank the C-clamp, measure the dent, calculate.

    I got about 5 for some pure lead I bought, and my air-cooled wheelweight ends up in the 10-13 range usually. Had a funny batch of wheelweight with peacock-colored dross that I eventually got rid of and the lead left behind gave me a BHN of about 6.
    I'm curious. Have you checked to see how many turns of the handle on your C clamp gets you to your target pressure? A little experimenting would tell a lot. If the number of turns remains constant from initial contact to target pressure and from alloy to alloy, you could eliminate the scale from the set up in the future. If the hardness of the alloy affects how many turns you need to reach the target, then you continue with what you have. Just wondering it a little testing might let you simplify your set up for future use. Inquiring minds....
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  15. #35
    Boolit Master .5mv^2's Avatar
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    I was wanting a hardness tester so I built my own version of one. I used a steel rod which I ground into a hemisphere, salvaged from an old computer printer. I used a tube to guide the rod onto the chunk of lead. Dropping the rod it created a dent in the lead. Starting with some soft lead to calibrate I dropped it, working backward and assuming a BNH of 5. Wrote a spread sheet to calculate the hardness vs the dent size using the published formula

    Hey it works... Most of my muffins are coming out 11 or 12.

    Since the formula doesn't specify the force or the diameter. Just input those into the formula. Using a decent sized diameter (.475") ball radius eliminates the need to view the size of the dimple with a microscope.

    Is it accurate, I am guessing so since the difference in dent diameter between soft lead and my alloy is about a third. I think I am going to vary the height to see if my nomogram holds up. Yes the Lee model is less than 50 dollars but being retired this will be fine.

    Thanks all for inspiring me.
    Last edited by .5mv^2; 03-14-2014 at 08:12 PM.
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  16. #36
    Boolit Master .5mv^2's Avatar
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    I decided to try two different drop distances up to 2'. I got almost exactly the same experimental values when run through the spread sheets. I used the constant force of gravity.
    "The purpose of the law is not to prevent a future offense, but to punish the one actually committed" Ayn Rand

  17. #37
    Boolit Master Markbo's Avatar
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    Just curious... are you an Engineer by trade?

  18. #38
    Boolit Master .5mv^2's Avatar
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    Red face

    Markbo, Na I'm a Jack off all trades I'm retired from working in the optical field, using math and science every day.

    I set up a spreadsheet to apply the formula found in wikipedia (we used a similar one for calculating radius based on the sagittal depth) and assumed that the BHN (for my soft lead sample) was 5 and solved for the impact force. For other samples I used the same force found in the pure lead sample and solved for BNH.

    My instrument is crude now. When I get the design cleaned up I'll post a few pics.

    I thought that I could use an auto punch and just punch the alloy and convert the diameter to BHN. Not sure how consistant the punch is though.
    "The purpose of the law is not to prevent a future offense, but to punish the one actually committed" Ayn Rand

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