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Thread: Genuine Brinell Hardness Tester, Cheap

  1. #1
    Boolit Master
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    Genuine Brinell Hardness Tester, Cheap

    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.

  2. #2
    Boolit Master
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    I'm envisioning a 220lb spring mounted with something like a lever-arm or a reloading press ram used to compress the spring upward allowing for placement of a lead sample underneath. Release the lever & start the timer.

    Thanks for the info.

  3. #3
    Boolit Master
    a.squibload's Avatar
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    Thanks!
    I'm too cheap to buy a tester, but this sounds like a good homemade system.
    Need to calibrate my bathroom-type scale, thought I weighed more, found out
    at a visit to the doc that I'm 15 lbs lighter! Adjusted my scale using a known quantity
    (40-lb bag of fertilizer). Hold bag and weigh myself, then drop bag and weigh again.

    Anyway I have some ball bearings of various sizes, will try it.

  4. #4
    Boolit Master
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    If you've got a Dillon RL550B, the spare parts kit comes with a 3/8" ball bearing. That's where I got mine. Also, a company called Small Parts sells small bags of ball bearings in various diameters and materials on Amazon (free shipping).

  5. #5
    Boolit Master
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    The Lee Precision hardness tester uses a 4mm ball - 60# force for 30 seconds because the formula for Brinell hardness is variable for ball size and force ...
    http://en.wikipedia.org/wiki/Brinell_scale
    So a 10mm ball and 220# force are not fixed factors to measure hardness

    And for 44 bucks (when on sale) - the Lee is no muss - no fuss and good to go anytime you want to pull the handle of the press.

    I find the Lee Tester a good investment (for me) because I make multiple alloys from multiple hardness ingots ... and then test them at least every several days while they age ... from an inventory of lead from Bhn 4.9 to 15.4 WW's - about 1800#'s last count

    Here is a better conversion chart than the one that comes with the Lee Tester ...
    http://www.frfrogspad.com/miscellm.htm#Brinell

    PS: I started life measuring using 2 bottle caps (pure PB and unknown) - a ball and using a vice for the force ... was a pure PITA!
    Regards
    John

  6. #6
    Boolit Master Stick_man's Avatar
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    If you happen to have a drill press kicking around, that would probably work as well (wouldn't even need to turn on the power) and be a little easier than dealing with a c-clamp. Might not be as easy to get a stable pressure though. Just kinda think out loud here.

    Set your scales on the press platter (table), set your jig on it to hold your test subject, have another jig set up with the ball bearing. I figure then you would be able to test much larger pieces of alloy.

    When you're done, a quick 20-30 second switchover and you are back to a drill press, ready to drill the next hole.

  7. #7
    Boolit Master
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    I use something similar with what I have on hand. I use a .312" BB an arbor press and a 22lb weight for 30 seconds.



  8. #8
    Boolit Master
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    Hello Zomby Woof,
    I like this way of doing this test, but have a question.
    Did you ever put a scale under the bullet to see what the pressure exerted was? I think that the length of the arm can make a difference in leverage that could effect the actual weight being applied.
    I think your results would be the same from test to test but I'm curious if changing the arm length would change the readings (dimple size).
    If you've already checked that then forget everything I said.
    Good idea though,
    Rog


    Quote Originally Posted by zomby woof View Post
    I use something similar with what I have on hand. I use a .312" BB an arbor press and a 22lb weight for 30 seconds.



  9. #9
    Boolit Master
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    I tried to put the scale under the press. It just didn't work. The scale is too big/press too small.

    I extend the arm all the way each time. Results are very repeatable.

  10. #10
    Boolit Bub eldoradolee's Avatar
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    Quote Originally Posted by zomby woof View Post
    I use something similar with what I have on hand. I use a .312" BB an arbor press and a 22lb weight for 30 seconds.


    Why,Why,Why???,Just buy a Lee tester.Over kill,to much work.Lee

  11. #11
    Boolit Master Sonnypie's Avatar
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    Quote Originally Posted by a.squibload View Post
    Thanks!
    I'm too cheap to buy a tester, but this sounds like a good homemade system.
    Need to calibrate my bathroom-type scale, thought I weighed more, found out
    at a visit to the doc that I'm 15 lbs lighter! Adjusted my scale using a known quantity
    (40-lb bag of fertilizer). Hold bag and weigh myself, then drop bag and weigh again.

    Anyway I have some ball bearings of various sizes, will try it.
    Darn, Squibload, if I used my wife's bathroom scale she'd probably poop a long worm.
    Besides, it's glass and I sure don't want to tell her I busticated it.
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  12. #12
    Boolit Master
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    Quote Originally Posted by Sonnypie View Post
    Darn, Squibload, if I used my wife's bathroom scale she'd probably poop a long worm.
    Besides, it's glass and I sure don't want to tell her I busticated it.
    Well, I'm safe on that count, it's my garage scale now.
    She doesn't like that scale, it started saying
    "This is not your zip code"...

  13. #13
    Boolit Master
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    The Brinell hardness value is in units of "kg / mm2". As such, the values that you use must be converted to metric for the numbers to work out to be the same that everyone normally quotes. You can use balls that are measured in inches or weights that are measured in pounds, but you need to convert them to metric prior to plugging them into the formula. Lee supposedly uses a 5/32" ball for their indenter, but I've seen people quote it as being a 4mm ball. They are not equivalent. A 5/32" ball would be 3.96875 mm.

    1" = 25.4 mm (exact)
    1 lb = 0.45359237 kg (exact)

    If you are designing your own hardness tester, you want to ensure that you are not using a ball diameter and weight combination that is such that it is pressing the ball down so far that the slope of the tangent to the curve of the ball at that point is so great that a small change in the indented diameter equals a large change in the BHN. With the Lee system, the ratio of the indention of the ball to the total ball diameter varies from 63% to 25% as you go from 5 BHN to 36 BHN. That is probably a pretty good ratio to stay with.

    So, let's say that you wanted to go from the Lee system of 5/32" ball and 60 lb load to a 5/16" ball. You would need about a 240 lb load in order to have similar ratios between the indentation and the total ball diameter.

    If you setup a spreadsheet to calculate the indentation diameters for various BHNs, the numbers get a bit flaky if you put a large load weight. It appears to show that the indentation diameter approaches the size of the actual indenter and then it *decreases*. Of course, that's wrong and what is really happening would be that the ball was being pushed all the way through the test material. Or maybe just that we're getting at the boundary area of the formula and things are not exactly right with how I'm using the equation at that point.

    The 10mm ball that is listed in Wiki for the Brinell test would need to use about 172.8 kg (380.95 lbs) as a load weight to get the diameter ratios that Lee uses for their tester. The 3000 kg of force that is listed in the Wiki article would result in the indenter being driven *though* the lead. You would actually need a indenter of around 41.7mm in order to work with a 3000 kg load force for lead. Now, looking on the bright side, at least with that size indenter, you would be making indentations that you did not need a 20X microscope to measure.
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  14. #14
    Boolit Buddy
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    Ok great ideas here. Using a set of bathroom scales, my drill press and a #4 steel shot I did a little hardness testing. 1st placed the scales on the table of my drill press, them placed a piece of 1/8" steel on with a boolit on it. #4 shot on chuck and ran it down on the boolit until the bathroom scales said 60 lbs. Held it for a 30 count. Released and measured with the calipers. Using the online calculator above here's what I got

    Range lead cast today 7

    Range lead cast last week 10

    Range lead cast 6 moths ago 12

    30 to 1 7.4

    20 to 1 11

    WW 13

    I think I will repeat the tests tomorrow.

  15. #15
    Boolit Master
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    Quote Originally Posted by Pmc View Post
    Ok great ideas here. Using a set of bathroom scales, my drill press and a #4 steel shot I did a little hardness testing. 1st placed the scales on the table of my drill press, them placed a piece of 1/8" steel on with a boolit on it. #4 shot on chuck and ran it down on the boolit until the bathroom scales said 60 lbs. Held it for a 30 count. Released and measured with the calipers. Using the online calculator above here's what I got
    Assuming that #4 steel shot is 0.130" in diameter, in order to have the same ratios of ball diameter to indentation diameter with a #4 steel shot, you would need to decrease the force to around 42 lbs. Concerns that I would have with using steel shot are the sphericity of the shot, the consistency of the size of the various shot that are purported to all be of the "same" size, and the fact that steel shot is often annealed to make the steel "softer". The latter issue might not be much of an issue on something as soft as lead though.
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  16. #16
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    Quote Originally Posted by WilliamDahl View Post
    Assuming that #4 steel shot is 0.130" in diameter, in order to have the same ratios of ball diameter to indentation diameter with a #4 steel shot, you would need to decrease the force to around 42 lbs.
    WilliamDahl,

    Been thinking about building a tester myself. I don't know anything about steel shot but do you think the smaller diameter ball would make the much smaller dents in the lead harder to measure and less precise? It just seems like the eyeball+calipers error in thousandths will be about the same whether the ball diameter is .130 or .375 and the smaller ball will penetrate up its sides in softer lead making increasingly smaller differences in diameter as it goes deeper. Real hardware stores like Ace and True Value usually have fasteners and odd parts bins that include steel balls in standard sizes. Failing that, almost every town has a bearing supply house that will probably have hard steel balls.

    Here are some interesting links on homemade lead hardness testers. Thre's another thread on this forum that shows a very nice home built hardness tester but I'm having trouble finding it. I'll post it when I get to my other computer that has the link saved.

    http://castboolits.gunloads.com/show...ardness-Tester

    http://mountainmolds.com/bhn.htm

    David
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  17. #17
    Boolit Master
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    Quote Originally Posted by David2011 View Post
    WilliamDahl,

    Been thinking about building a tester myself. I don't know anything about steel shot but do you think the smaller diameter ball would make the much smaller dents in the lead harder to measure and less precise? It just seems like the eyeball+calipers error in thousandths will be about the same whether the ball diameter is .130 or .375 and the smaller ball will penetrate up its sides in softer lead making increasingly smaller differences in diameter as it goes deeper. Real hardware stores like Ace and True Value usually have fasteners and odd parts bins that include steel balls in standard sizes. Failing that, almost every town has a bearing supply house that will probably have hard steel balls.
    With smaller balls, you have to use less weight. I have a spreadsheet that I use to calculate the indentation diameters for BHN 5-36, given a ball diameter and the force used. I also calculate the ratio of the indentation diameter to ball diameter to keep it in the same range that Lee is using. I'm assuming that they actually put some thought into the force and ball diameter combination that they used and that it results in acceptable accuracy. Measuring it via a caliper is not going to be as accurate as a microscope / comparator with graduated scale markings embedded into the lens. This is basically what Lee provides with their 20X "pocket microscope". You can buy this sort of thing for around $10 at DX.com.

    Now, on the other hand, if you already have a spare computer and scanner in your reloading room, you can use it instead of using a pocket microscope. Here's a description of the process:

    http://www.tacticoolproducts.com/brinell/

    Probably works well enough for small pieces of lead (bullets, small ingots, etc), but if you are wanting it to measure some large piece of lead at a scrap yard, it's just more equipment that you would have to take with you and would not be that compact of a solution.
    Last edited by WilliamDahl; 03-11-2013 at 04:22 AM.
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  18. #18
    Boolit Master
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    After a bit of research, I think I've found a source for a high grade ball bearing that would be perfect for the indenter ball -- bicycle ball bearings. They are commonly available in Grade 25 (i.e. 25 millionths of an inch sphericity tolerance). They are fairly cheap online or if you happen to be driving around and see a bike shop, they would probably sell you one for a few cents. Checked online and found a company on eBay selling a bag of 20 of the 3/16" ones for $1.90 plus $1 shipping. For 3/16" balls, you'll need around 86.4 lbs force to get the same ball to indented ratio that Lee uses. I'm sure that there's a bit of fiddle room in that, so it's not as important to be exact as it is to have a high degree of repeatability.
    NATURAL BORN CITIZEN = offspring of TWO US citizens
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  19. #19
    Boolit Master Markbo's Avatar
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    All this time & effort and what ifs and how abouts really makes me appreciate my simple Lee tester.

  20. #20
    Boolit Master
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    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 ...

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