Cheap way to test Lead Cast hardness

[hunter64]

I was reading a book from the late 50's at a friends home that was put out by the NRA on how to test lead hardness on the cheap. I gave it a whirl and it works great so I thought I would share for those of you who are cheap like I am.

You need about 2 pounds or so of pure lead, your test lead and a steel ball bearing and a vise and a set of calipers/micrometer and that is it.

To get the pure lead you can find it in a metal supply shop but it runs about 3-4 bucks a pound or you can save the stick on weights when you find them in your bucket of wheel weights. I bought a couple of pounds to see what the difference was between it and the stick on version and the bhn number is about 5.2 or 5.3 instead of the 5 for pure lead, so close enough.

Drop by a bearing shop and pick up a 1" steel ball bearing and that costs about 2 bucks or so.

Melt the pure lead(stickon weights)in a muffin tin and your test lead in the one muffin slot next to it. I waited a day to test because I am anal that way.

Pad the vise with aluminum or steel on the jaws so that the lead doesn't dig into the teeth of the jaws. Hold up the lead in one hand and the test lead on the other jaw and slowly squeeze the two together with the ball bearing in the middle. Just squeeze till there is a good dent on both surfaces of the lead or about 1/5 or the way in on both sides of the ball bearing.

Here is the formula BHN= 5 X (lead dia./test dia.)^2

With the calipers measure the diameter of the indent in each of the leads and plug in the values.

I had some WW and an unknown lead from a Radiator shop that I wanted to test and here are the results.

Diameter in Lead=0.479
Diameter in WW=0.325

So 5 x (0.479/0.325)^2 and that gives 10.8 BHN where it should be for air cooled Wheel Weights.

I had my friend test the WW on his Lee Hardness tester and he came up with 11so close enough.

Unknown lead from radiator shop

Dia. in Lead=0.520
Dia. in Unknown=0.279

So 5 x (0.520/0.279)^2 which gives us 17.4 BHN

I knew it was harder just with the old thumb nail test but I had no idea it was that hard. Again on the lee it came back as 17 BHN

So this is a great cheap way to test lots of lead, it won't work so good on single bullets like the expensive models but at least you know what the raw materials BHN number is approximately.

My 2 cents worth for those cheap suckers like me.

[Bucks Owin]

Hey, cool tip....I'll try it

Thanks,

Dennis

[chunkum]

Good tip. Thanks.
c.

[Ken O]

The method I use is to take an Arrow T-50 stapler using 3/8" staples and measure the penetration of the staple using a dial caliper. Actually you measure the amount that protrudes.
.111 lead 5 Bhn
.188 WW 9 Bhn
.212 2-6 alloy 15 bhn
.245 Linotype 22 bhn
So if you have some pure lead, staple it, measure and use that for your calibration and go from there.

This came from The Cast Bullet Journal No. 129 Sept/Oct 1997 p. 15. I typed up the article, but don't have it on computer to reproduce the whole thing which is kind of lengthy. Maybe someone else has it and can scan it if there is interest.

[Edward429451]

In <5 x (0.520/0.279)^2>, what does the ^2 mean?

Forgive me. Math was my worst subject! I thought I knew what it meant but it gave me 12.8 instead so thought I'd ask.

[imashooter2]

In <5 x (0.520/0.279)^2>, what does the ^2 mean?

Forgive me. Math was my worst subject! I thought I knew what it meant but it gave me 12.8 instead so thought I'd ask.

It means "squared" or "times itself". 3^2=3 x 3=9

[robertbank]

So your formula is:

BHN= 5 X ((lead dia./test dia.) * (lead dia./test dia.))

Sorry I missed the value of ^ in your post as well.

Would the lead you find in the core of jacketed bullets be pure lead? Thinking of using a pound of it as a control base.

Take Care

[NucEm]

If anyone has problems finding pure lead, try using any soft mettal to test with, as long as you know the bhn number of it and change the formula it works.:) I have used pure copper in my:-D
But now iam gonna try to find my staplegun and start shooting on bullets:Fire: sounds a lot faster:)

[kywoodwrkr]

hunter64,
Outstanding passing along of valuable information.
I copied your narrativeand wrote out the formula in an EXCEL spreadsheet.
Now as long as I don't misplace my jump drive-I've got it made.
Thanks.
DaveP

[Leadmine]

When you use the staple gun method there are a few things to keep in mind. I always do the work on a bathroom scale since the amount of pressure applied should be constant. It won’t work for bullets, you will need ingots or larger pieces for your sample. I have found that the calibration curves are generally linear so you can calibrate your stapler with just two samples such as pure lead and linotype. The staple will typically deform, but that is no problem. What you will measure with your calipers is the amount of staple (measure the staple post) which is protruding from the sample, as Ken O describes. The more staple post protruding (larger measurement) means a harder sample. If you take the time to draw the calibration line, I think you may find the technique is quite accurate. Some staple lengths might work better than others as well as some staple guns might work better. Take some time and play around with some of these variables.

I was delighted to see that someone is using this technique. I am the author of the original article which was written almost ten years ago.

Thanks!

Dave

[Edward429451]

Thanks for pickin up my math slack imashooter. I have some ingots that some are hardened and some pure lead, that my kids mixed up for me when the did dad a favor and cleaned up the garage. Some are WW's too.

I have a T-50 and the bearing sho[ is right around the corner so I'm gonna try both methods and sort my ingots.

Great tip(s)!!

[grumpy one]

Thanks for pickin up my math slack imashooter. I have some ingots that some are hardened and some pure lead, that my kids mixed up for me when the did dad a favor and cleaned up the garage. Some are WW's too.

I have a T-50 and the bearing sho[ is right around the corner so I'm gonna try both methods and sort my ingots.

Great tip(s)!!

I always write a code on each ingot with an electric pencil as soon as they cool after casting. I keep it simple: "WW", "3/5", "LT", etc. It doesn't have to be my kids who mess me about, I'm pretty good at doing it myself, and I find it very beneficial to be certain which alloy I'm handling. I guess the same outcome could be achieved by using different ingot moulds for different alloys.

Geoff

[Edward429451]

I started doing that as soon as I realized they were mixed up. I have a metal stamp kit and stamp them W for WW's, L for lead and H for hardened w/tin.

I havent been using the mixed ones. Soon I'll sort em out and stamp them too.

[Topper]

Very informative post.
Thanks for sharing the info;-)

[garandsrus]

Leadmine,

Would you be willing to re-post the article on this site?

Thanks,
John

[Ken O]

When you use the staple gun method there are a few things to keep in mind. I always do the work on a bathroom scale since the amount of pressure applied should be constant. It won’t work for bullets, you will need ingots or larger pieces for your sample. I have found that the calibration curves are generally linear so you can calibrate your stapler with just two samples such as pure lead and linotype. The staple will typically deform, but that is no problem. What you will measure with your calipers is the amount of staple (measure the staple post) which is protruding from the sample, as Ken O describes. The more staple post protruding (larger measurement) means a harder sample. If you take the time to draw the calibration line, I think you may find the technique is quite accurate. Some staple lengths might work better than others as well as some staple guns might work better. Take some time and play around with some of these variables.

I was delighted to see that someone is using this technique. I am the author of the original article which was written almost ten years ago.

Thanks!

Dave

Yep, I have two igots that are my calibrators, one pure lead and one linotype. The staples are deformed and look like a "M", but it doent matter, just measure the legs. Real simple, not rocket science at all using this method.

[357maximum]

Ken O, and Leadmine

That is what I love about this site, always something new to learn. I have really been thinking about how to CHEAPLY measure relative hardness, I tried the ball bearing thing with bottlecaps, but math has never liked me much. Measuring the distance with a staple penatrometer on an old baby scale should suit this cheap @$$ man to a T.

PERFECT

thanks

[StarMetal]

Some of you newer members won't remember this Troll we had, by the name of Aladin, who claimed he tested the hardness of his alloy by hitting the ingots with a hammer. He's no longer with us.

Joe

[Leadmine]

Here is the paper I Sent to Cast Bullet Association. The graph and table don't show up, so I attached the document as a WORD.DOC below. Look at the document because the table and graph are probably as important as anything.



A Simple Method For The Determination of Alloy Hardness By: David Berry

This describes a method for the determination of lead alloy hardness. It is a simple, quick, and economical means to test hardness of unknown alloys, and I have found it to be reliable and accurate.

Using a common staple gun, I have found that measuring the penetration of the staple into the alloy can be used to determine relative hardness when compared to a series of "standard" known lead alloys. I simply inject a staple into the sample and measure the post of the staple that protrudes. I obtain 5 readings on each known standard, average them and prepare a calibration chart versus known BHN values. A sample chart is shown below. Unknowns are then subjected to the same procedure and the resulting measurements are compared on the chart to determine relative hardness.

ALLOY
1
2
3
4
5
Ave
BHN

Lead
0.102
0.107
0.115
0.109
0.12
0.111
5

Wheel weight
0.209
0.18
0.186
0.177
0.186
0.188
9

2-6 Alloy
0.223
0.216
0.217
0.19
0.214
0.212
15

Linotype
0.255
0.24
0.238
0.258
0.234
0.245
22


5 readings for each alloy in inches





Arrow T-50 stapler







3/8" staples









I first started working on 1 pound ingots of the same size, but found that size or shape is not all that important, the sample just needs to be large enough to hold the staple gun onto it. I apply about 20 pounds of pressure on each sample (determined with a bathroom scale) while I inject the staple. I have used a Bostich electric staple gun and this works well also. A 3/8 inch staple is about the largest that can be used as longer staples deform. This can be overcome by measuring the actual penetration by subtracting the protrusion as measured above , from the total length of the staple post.

Each staple gun must of course be calibrated as will the batch of staples being used.

I find this to be an extremely easy method to determine alloy hardness, and by measuring several samples have determined it to be very reliable and fairly accurate. It works very well on odd sample shapes and sizes.

[Leadmine]

Some of you newer members won't remember this Troll we had, by the name of Aladin, who claimed he tested the hardness of his alloy by hitting the ingots with a hammer. He's no longer with us.

When I was looking for a simple method one thing I tried was dropping ingots onto a concrete floor and measuring the sound with a cheap guitar tuner which actually registers a number on a gauge. I thought I might be able to construct a calibration curve similar to what I did with the staples. We all know that different alloys make a different "ring". The method did not work because I could not easliy control the way or direction that the piece hit the floor. Plus sample sizes would have to be the same...I think. Another problem was it took two people and my wife was getting tired of dropping ingots from exactly 4 feet. If someone could find a way to strike the ingots resulting in a consistant "ring"they might be able to register on something like a guitar tuner. Hitting them with a hammer would result in too dull a sound. Anyways, I didn't work too long on my "sound" method before giving up, although it might be possible with some better ideas on how to control the sound emitted.

[garandsrus]

Leadmine,

Thank you very much.... I will give the stapler method a try!

John

[w30wcf]

Leadmine,

THANK YOU for posting your development of testing BHN with a stapler. I remember reading your original article in the CBA newsletter. Wonderful idea!

Ken O,
THank you for the reminder.

w30wcf

[hunter64]

Never heard of the stapler method either. The article that I had was from a cast lead book of reprints from the 50's and 60's that the NRA put out. It was about 100 articles from various authors on cast bullets and it is very good for a quick reference. I tried heat treating and it came back with a BHN of 26 which is about right. The only thing I can see that you would have to play with the stapler method is the spring power in the stapler itself. I have three staple guns and no two are the same. So I guess if you tested the lead and then compared it to the staple method as a reference for your specific stapler that would work. I write on my ingots with black felt what they are but I have been thinking of getting a metal punch set also to engrave them. I have a cast iron bread loaf pot that you use to make bread in and it holds exactly 25 pounds of lead and I use that to store the lead in. I have them lined up on the back wall in the garage and I can see at a glance how much lead I have and I have them categorized by type. When I go to use them I just cut them in 1/4's with the band saw and into the pot.

[357maximum]

I have one of the newer staple/brad gun combo's that I am goin to play with, both staples, and the little brads...Great idea...Great idea, did I mention, this is a great idea...

[Newtire]

How about Turner Kirkland's method of testing lead to see if it was soft enough to obturate in a muzzle loader. He said that if you could indent it with your thumbnail, it was pure lead but if you couldn't, shoot it anyway.

[redneckdan]

I have soft scrap that measured 6ish on the brinell scale, so soft you can gouge it with a finger nail. If you drop two ingots together, they ring pretty well. SUposively the better they ring the harder the alloy, guess it ain't quite true.

[John Boy]

Leadmine ... Thanks Kindly for posting and the Word doc also. Tucked it away in my casting references.

Another easier way to test using the ball bearing method is:
...Pour pure Pb into a bottle cap (Save for future use- needs to be re-heated for a smooth surface though)
...Pour unknown alloy into another bottle cap.
Then do the ball bearing squeeze in the vise and calculation.

The new modern 'Millie' for this method is the Lee Precision Hardness Tester ... about 40 bucks at Midway on sale. Using the Lee die with a 'bearing point' and their graduated magnifier to measure the width of the impression... accurate Bhn results can be obtained for any alloy.

[hunter64]

I actually tried the ball bearing method on a 44 mag bullet. Poured one of pure lead and then of my mixed stuff, water quenched. Put them in the vise with a small ball bearing between the bases and away we go. I have such big fingers it was a pain to get everything held together to test it but it did work and gave me the same number as a big 1 pound ingot did.

I think the brad nailer would work good also, set at a specific air pressure and do your calibrations with a known good measurement and away you go.