Best way to use Lee hardness tester

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  • Last Post 01 August 2014
John Alexander posted this 17 February 2013

I have been using an LBT hardness tester since shortly after Veral put them on the market years ago. I am well satisfied with the LBT gadget but recently ordered a Lee Hardness Testing Kit because its approach is closer to the real ASTM Brinell hardness test apparatus.

The Lee kit consists of a calibrated ball indenter to make dents in the test specimen under a set load, a V block gadget to hold bullets in a horizontal position for testing, and a small 20X optical microscope to measure the diameter of the dent. After an hour of trying to take readings on a variety of lead alloys I was very frustrated. I have no quarrel with the quality of the equipment but I found two problems.

First as might be expected with any 20X optical device it was difficult to get good reading with the microscope while holding it free hand even when I tried bracing my hand in various ways.

Second, I had difficulty arranging a light source to eliminate glare from the shiny lead surface making it hard to get repeatable readings.

It seems to me that some sort of mechanical holder is needed for the microscope. I asume the glare problem can be solved with some sort of low power adjustable light.

Before trying to reinvent the wheel I thought I would ask how others have solved these problems.

Any advice will be appreciated.

John

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Coydog posted this 01 August 2014

This is how I use the Lee tester It is not a fancy set up but it works for me

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Larry Gibson posted this 31 July 2014

onondaga wrote:  http://www.castbulletassoc.org/view_user.php?id=7953>csparks1106

Fast cooling of alloy drastically effects hardness in any alloy that contains Antimony, a cold mold or quenching can increase hardness 5 or more points in BHN,

Pour into a hot mold 100 degrees or less than the temperature than the molten alloy and allow to cool of it's own accord and you will get the lowest and truest BHN test results.

You can also draw heat temper out by heat soaking bullets or ingots at 425 degrees or so for an hour and turn oven off but leave closed to cool slowly for a few hours.

Gary Once I started measuring BHN I found a great disparity of hardness in ingots of the same alloy.  I found that the ingots that were poured when the Lyman cast iron ingot mould was cold and setting on the cold cement (40 - 60 degrees) floor always had a harder BHN than the ingots that were poured when the ingot mould was hot.  Usually a 3 - 5 BHN difference.    When WQing I find if I adjust my cast tempo to open the mould just as the sprue is hard (usually a 3 - 5 count after it turns grey) and drop the bullets as quickly into the water as possible the BHN of COWWs + 2% tin or #2 alloy is increased 7 - 10 BHN.  I cast at 725 degrees (thermometer).   LMG

Concealment is not cover.........

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gpidaho posted this 31 July 2014

Gary:  Your observations BHN  are a point well taken, though I own a Saeco hardness tester I dont use it much anymore.  Too many alloy variances read the same and perform differently. As you mention there are many things along the way from scrap to bullet or ingot that effect the reading. Trial and error experiments work best for me and most of what I shoot just falls in the WW+ Tin range anyway. Hope your showing some improvement health wise.    GP

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csparks1106 posted this 31 July 2014

onondaga wrote:  http://www.castbulletassoc.org/view_user.php?id=7953>csparks1106

Fast cooling of alloy drastically effects hardness in any alloy that contains Antimony, a cold mold or quenching can increase hardness 5 or more points in BHN,

Gary I've read about quenching, and I haven't done that. However, the ingots were poured into a cold muffin tin sitting on a concrete floor. Perhaps that's the cause. I'm going to check some of the bullets and see what their bhn number is.Thanks Gary.

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onondaga posted this 31 July 2014

 http://www.castbulletassoc.org/view_user.php?id=7953>csparks1106

Fast cooling of alloy drastically effects hardness in any alloy that contains Antimony, a cold mold or quenching can increase hardness 5 or more points in BHN,

Pour into a hot mold 100 degrees or less than the temperature than the molten alloy and allow to cool of it's own accord and you will get the lowest and truest BHN test results.

You can also draw heat temper out by heat soaking bullets or ingots at 425 degrees or so for an hour and turn oven off but leave closed to cool slowly for a few hours.

Gary

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csparks1106 posted this 31 July 2014

Ok, I need to verify something. According to the cast bullet handbook, ww lead should come in around a bhn of 9. I'm assuming that's clip on type ww. I have checked several of my ingots. All clip on ww. Several different batches and from different sources. They are coming out much higher than 9. Most are in the 14.3 range. This has me concerned I am using the tester wrong or it's not calibrated wrong. I place an ingot on the press ram. Run it up to the indented and press it up until the rod is level with the top of the tester. I begin my timing as soon as I begin the lifting process. I hold it for 30 seconds by my watch. The process is the same for the bullets except I use the little bullet holder in the shell holder. Am I doing something wrong? 

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TRKakaCatWhisperer posted this 27 July 2014

LWesthoff wrote: If that's an aluminum muffin pan I see lurking under the ingot molds in the last picture TRK posted, that will probably make the smoothest surface you can get (and you don't have to sand it). I've been using cast “muffins” for testing for a long time. Just be sure your muffin pan is aluminum, not tin plated iron!

Wes YUP the muffins are SMOOTH.  I cast up about 100 lbs of TIN each year and keep to the smaller ingot moulds.  For lead alloy I make up 30 lb cylindrical ingots because I did two batches 300 and 400 lbs or so of everything I had - sorted into 30:1 lead/tin and 20:1 WW / tin.  From there as needed remelt to smaller ingots.

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LWesthoff posted this 27 July 2014

If that's an aluminum muffin pan I see lurking under the ingot molds in the last picture TRK posted, that will probably make the smoothest surface you can get (and you don't have to sand it). I've been using cast “muffins” for testing for a long time. Just be sure your muffin pan is aluminum, not tin plated iron!

Wes

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TRKakaCatWhisperer posted this 27 July 2014

and cast iron (about $10 to 12 each)

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TRKakaCatWhisperer posted this 27 July 2014

a bit rusty from being outside.  

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TRKakaCatWhisperer posted this 27 July 2014

another

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TRKakaCatWhisperer posted this 27 July 2014

A few pix.  You're likely past this stage.  

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onondaga posted this 27 July 2014

I use cast iron Lyman ingot molds.. They are not very smooth. I prefer a smooth surface for the ball of the hardness tester to get best repeatable results.

My grandson starts welding classes this fall. I'd like to ask him to weld up some of the cut flat steel stock ingot molds that I have seen others post about! I actually like the 5 pound size Lyman #2 ingots I get from RotoMetals, they stand up nice in my Lee 4-20 bottom pour pot.

RotoMetals #2 Lyman 5 pounder:

http://s30.photobucket.com/user/rhymeswithwhat/media/PB040045_zpsa3d9a5a7.jpg.html>

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Larry Gibson posted this 27 July 2014

I also use a Lee Hardness tester mounted in a microscope.  It makes it's use fast, easy, repeatable and very precise.  I also have “calibrated” my Lee scope using pure lead and using the formula for conversion.  The Lee tool also measures in .001” so it is easy.  The Lee table of BHNs is pretty close.  A small piece of cardboard with a bit of modeling clay on it hold the bullet and makes it easy to line up the indent with the scope scale.   I also use multiple tests on a sample and record the average BHN reading or the ES of the readings.     LMG    

Concealment is not cover.........

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csparks1106 posted this 27 July 2014

onondaga wrote: Csparks1106

I test my own ingots but trust no one Else's ingots. Cooling of ingots is too frequently done by  others with water and this gives very false hardness readings to any hardness test.

You shouldn't be surprised either,  that alloy poured into a cold ingot mold or cold bullet mold will give a false hardness reading.

I use a belt sander to make rough ingots smooth for hardness testing. Use a filter mask when abrading lead and vigorous hand washing when done handling lead to avoid lead absorption to your lungs and hands.

Gary Why do you sand the ingots? Mine are pretty smooth right out of the muffin tin. Are you looking for a mirrored surface or getting past the contact layer?

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onondaga posted this 27 July 2014

Csparks1106

I test my own ingots but trust no one Else's ingots. Cooling of ingots is too frequently done by  others with water and this gives very false hardness readings to any hardness test.

You shouldn't be surprised either,  that alloy poured into a cold ingot mold or cold bullet mold will give a false hardness reading.

I use a belt sander to make rough ingots smooth for hardness testing. Use a filter mask when abrading lead and vigorous hand washing when done handling lead to avoid lead absorption to your lungs and hands.

Gary

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gpidaho posted this 27 July 2014

Good morning John:  If you don't mind looking at that other forum there are many threads showing all kinds of ingenious little stands and optics for the little device. Search Lee hardness tester, go to stands and check it out, well worth a look.  Regards   GP

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csparks1106 posted this 27 July 2014

Gary, I noticed in this post you are measuring ingots and not bullets. I find it much easier to measure in this fashion, as it's much harder to hold a small bullet still than a 2.5 pound ingot. Just to confirm from someone with more experience than myself, I am holding the Lee scope 90 degrees from the face of the ingot. I am testing the bottom of the ingot as it's much smoother. These come from muffin tins. Does that seem like an accurate means of testing?

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joeb33050 posted this 25 December 2013

madsenshooter wrote: Once upon a time, somewhere online, I read about snapping a digital pic of an indent and converting pixels to inches.  Probably never find it again.   I have little digital microscope ought to work pretty good for shooting the pic, if I ever do find the idea again. Here's a way to measure groups. A similar approach could be devised usin g a drill of known diameter perhaps as the reference.

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TRKakaCatWhisperer posted this 25 December 2013

I have considered it. But with a calibrated 50 lb weight there should be very little that would require recalibration over a long period of time. (I don't think that gravity changes much and the weight just needs dusting off annually.)

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