Hardness tester

[Snakeoil]

With winter here, my brain tends to wander in search of winter therapy projects to keep my mind occupied. Since I started shooting and casting again after a long hiatus, I have been using drawing pencils to determine the hardness of lead and it's alloys. The pencils seem to do a decent job, but they are subject to operator error. I have a friend with a SAECO hardness tester, but that requires a bullet shaped sample and to me, that is too limiting. I want something I can use on any piece of lead I come across.

I have been looking at commercially made testers and looking for used ones on Marketplace. So far, with the exception of some testers used to measure the durometer of rubber products, all I find are Rockwell testers. I looked at the Lee and that design is very appealing except for the need to use a loading press. But the basic design of the Lee follows the same design of the commercial testers in that they make an indentation with a sphere of known size and then knowing the force put on the sphere, it's diameter and the diameter of the indentation, one can calculate the Brinell number for that sample.

So, I'm thinking about building a tester. Design would be very similar to the Lee, only not require a loading press. It would still require something like a jeweler's loupe and a set of dial calipers to measure the indentation.

This may not progress the idea stage. I come up with these ideas at night and then when the next day comes, my interest often fades.

 

[Rick]

With winter here, my brain tends to wander in search of winter therapy projects to keep my mind occupied. Since I started shooting and casting again after a long hiatus, I have been using drawing pencils to determine the hardness of lead and it's alloys. The pencils seem to do a decent job, but they are subject to operator error. I have a friend with a SAECO hardness tester, but that requires a bullet shaped sample and to me, that is too limiting. I want something I can use on any piece of lead I come across.

I have been looking at commercially made testers and looking for used ones on Marketplace. So far, with the exception of some testers used to measure the durometer of rubber products, all I find are Rockwell testers. I looked at the Lee and that design is very appealing except for the need to use a loading press. But the basic design of the Lee follows the same design of the commercial testers in that they make an indentation with a sphere of known size and then knowing the force put on the sphere, it's diameter and the diameter of the indentation, one can calculate the Brinell number for that sample.

So, I'm thinking about building a tester. Design would be very similar to the Lee, only not require a loading press. It would still require something like a jeweler's loupe and a set of dial calipers to measure the indentation.

This may not progress the idea stage. I come up with these ideas at night and then when the next day comes, my interest often fades.

Houston, we have a problem. What determines the final BHN of a lead alloy is its rate of cooling. The exact same alloy cast into either a bullet or an ingot will give you two different readings because the much smaller bullet will cool much fast than the larger ingot.

I don't know if Veral still has or is selling them, but I highly recommend the LBT tester.

 

[Dusty Bannister]

Perhaps I should post this in the "Humor" category. I did make one of those highly portable indent lead hardness test items. Keep in mind this was a very Rube Goldberg creation. I had some long heavy bolts that had been used on RR ties or something similar and were something on the order of 3/4" by 12". Cut off the head of the bolt, cut a screw driver slot and rigged it up so I could turn it as I used a grinder to form a new point with about a 90 degree angle. I blunted the tip just a little thinking it would get buggered up anyway. I happened to have a piece of copper tube about 3-4 ft long and the fabricated pin was a loose slide fit in the tube. With a lino type ingot, a clip on WW ingot and a "pure" lead ingot, I established three reference points.

I prepared each ingot so there was a flat spot about an inch across. I then placed the end of the tube over the flat spot, held the tube vertical, inserted the pin to a well marked reference point and let it free fall and leave an intent in the ingot surface. I carefully draw filed the raised material down to the original surface. Easy to see when the strokes are at 90 degrees to each other. Then with a good light, caliper and magnifying glass took a reading and created a chart. With the three reference points, you can sort of "SWAG" the other readings by loosly following the charts shown on the Saeco chart. Hardness is not linear so while it is not accurate, for some it might be better than a thumb nail scratch.

So with a copper tube, a steel pin, and the chart you can test about any sized sample as long as you can get a flat spot to test. I presently use the Cabin Tree tester but still have the "RED' (Rough Estimate Device) testing tool.

 

[Ian]

A ball bearing, bathroom scales, nd some arithmetic will get you there. I use a Lee tester kit and find it very accurate (have compared results against other testing means) and very repeatable.

Heed what Rick wrote. The Lee tester comes with good instructions but doesn't explain rate of cooling with ternary alloys. Prepare to get wrapped around the axle as you test right after casting, the next day, every day for a month and graph the results. What many of us say about waiting a few weeks after casting before shooting a certain alloy will begin to make sense when you see what happens from these tests. Always test a group of bullets, not just one; this is what culls are for unless culled for temperature reasons.

 

[farmboy]

As Rick stated it depends on how fast the bullet cools. What effect does it have if they are water dropped? I use a Cabine Tree tester and trust it.

 

[Snakeoil]

I understand the points you all made. I have to admit, that Dusty's tool is elegance in simplicity.

My intent is not to test the bullets I make. The need is to test scrap lead I find to see what I'm dealing with purely from a hardness POV. A member at the club as a lot of lead from years past. I bought a bunch off him that was supposed to be soft lead. It tested to be pretty hard with my pencils. But then I hit the various lumps/ingots with a file to get down to virgin metal and found that they were all in the 20:1 range, which is what i use for my .30-06 in my 03.

I also have access to pretty much an endless supply of range scrap if I want to spend a day or two prospecting and screening lead out of the berms at the club. So, if I do that, I'd want to melt it down and see what I get from the Heintz 57 mixture.

I found a great article on testing lead hardness testers. I imagine those here like Ian and others have seen this article. Here is a link to that article for those who maybe curious/interested.

Shay Cast Bullet Alloy BHN Test Equipment Comparison

The formula I mentioned above is in an article written about using the Lee Hardness tester. You can plug that formula into Excel and create a spreadsheet for any homemade tester. The author found the formula in Wikipedia. Here's a link to his article.

https://www.castpics.net/subsite2/HowTo/Leehardnesstester.pdf

The LBT tester is no longer available. Veral's shop burned to the ground and destroyed all the specialized equipment he had made to produce molds and the lead hardness tester. Their website says this the permanent end to their mold and tester business. But they will start to make lube again when they can get set back up.

 

[popper]

Just cast some bullets you know (measure). Take them with you and a hammer. Place against unknown and hit. Look at the dents. I just put known and unknown in vice and squash, look at dents. Tells me all I need to know.

 

[JonB]

I've bought lots of scrap...different hardness scrap. If it's unknown, it has gotta be cheap/free, or I'm walking away. So, knowing the precise hardness isn't really that important to me. I use the Drop test.
Drop a chunk of pure or near pure lead on concrete and listen (thud).
then drop a chunk of COWW alloy on concrete and listen (ting).
then drop a chunk of linotype alloy on concrete and listen (ringing).
record those sounds in your head, for when you go scrounging for scrap lead, it'll tell you everything you need to know.

 

[Snakeoil]

I don't disagree with either of you. But I'm wired to want as much info as possible. Plus I enjoy the learning process.

I have been watching Marketplace for scrap lead since you can't buy it at the scrap yard anymore. Soft, near pure lead is going for about 41 cents/lb. I see folks listing unknow scrap lead or even sheet lead which should be pretty pure, and they are getting asking and getting over $2/lb for the stuff. If I have to pay $2/lb, I'll buy new stuff from NEI or Rotometals.