Homemade Lead Harness Tester

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  • Last Post 02 October 2016
NantachieRat posted this 29 March 2014

I work in a machineshop and I was able to come in after hours and fabricate a lead harness tester based on a short article in the Lyman cast bullet handbook  3rd edition. I will have a drawing and photos posted shrortly. I made it with a 7/8” x 14 thread to screw into my press and also made a sample mould and special blank shell holder to fully support the sample so as to not introduce any distortion in the sample. The penatrator is a 9/16” rod with a 3/4” head to hold it in place. A 7/8” 16 threaded plug holds the assymbly together. I made everything on a medium size engine lathe and milled the hex on the plug with a Bridgeport mill. I used a CNC turret lathe to turn a 10 mm radius on the end of the rod. 10 mm penetrators are the industry standard for checking Brinell hardness. Since I am only testing lead alloys, no heat treatment was needed. I am using a 100 lb spring as a load.

If anyone is interested I can share more details. If there is any interest in purchasing a unit, I will see about writing the programs to make the entire assymbly on CNC machines.

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RicinYakima posted this 30 March 2014

I'd love to see how you did it! Ric (and argie1891 and Uncle Russ)

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NantachieRat posted this 30 March 2014

As soon as I can bum a camera I will upload some pictures. I am also going to do an Autocad drawing. I just made it by looking at the pictures in my Lyman cast bullet handbook, so stay tuned!

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Tom Acheson posted this 30 March 2014

IF yours is like the one my friend made for me, I think it is a neat way to fool around exploring alloy hardness. Different springs can be used but the user needs to use a known pure lead sample to eventually get to the point where the diameter of indents in lead are established. Then you conduct the same sequence of events with the alloy and compare the indent made in it to the dia. of the lead indent. Then some simple math and the bhn is the result.

He made half a dozen of them and gave them away to a few closest friends. I'm one of the lucky ones and appreciate the effort and time he took making these cool tools.

Now to see what hardness my 16:1 BPCR alloy is.

Tom

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NantachieRat posted this 30 March 2014

I will borrow my Mother-In-Law's camera this evening and take some pictures and post them. It sounds like your freind's design is very similar to mine!

My Lyman cast bullet handbook says to multiply 5 times the indent in lead over the indent in the sample (5 x Pb/Sample) to get the BHN. I have a manufacturing engineer's handbook I use for work that gives a more complex formula based entirely on the diameter of the penetrator and the applied load. This allows one to test the BHN of any material, but a hardened steel ball penetrator would be needed.

We use mostly 304 & 316 stainless, Monel, Hastaloy, and Inconel X625 at work. We occasionaly use duplex stainless and alloy 20 stainless. I made the tester out of 416 stainless scraps we had on hand. When we recieve these materials from the supplier, it comes with a certificate showing the exact proportions of the alloy, the heat number of the melt, and the physical properties. The hardness is always given in BHN. The customers we ship parts to always require a copy of these certificates. The heat number of the material is always written on the copy of the drawing of the part and filed in the shop office with each order.

This gave me the idea of assigning heat numbers to my batches of alloy. I use a 5 qt cast iron pot to mix a relatively large amount of alloy ( about 75 lb's) I then pig it out into 1 & 5 lb ingots and fill my 1.5 qt casting crucible. I take all of these ingots to the shop and stamp my heat number on them. This heat number stays with each run of bullets and I weigh a couple of dozen to see what the weights will be. I have always wanted to be able to check the hardness as well. I also 'mash test' some bullets on a small hydraulic press to see if they will expand properly.

I am basically using Lyman No. 2 alloy. I mix 1 lb of 95% tin 5% antimony Pb free solder to 20 lb's of wheel weight metal. The 'mash test' shows no brittleness at all. My favorite load is the Lyman 311284 bullet (210 grs.) with 43 grs. of IMR 4064 on a .30/06 1903 Sringfeild Mk1 with a “C” type stock. Dead animal carcas testing shows this to be a deadly load with plenty of knock-down power. The exit wounds are on par with factory softpoint loads. There is no leading at all in the 4 groove barrel. Velocity is in the 2400 fps range.

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mrbill2 posted this 30 March 2014

That would make a excellant article to be published in the Fouling Shot.

mrbill2

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NantachieRat posted this 30 March 2014

I would be honored to publish an article about this in the Fouling Shot! How can we set it up? This would help fellow shooters alot.

The unit I built is just a basic prototype, but I can begin working on a production model. It would be no problem for my boss and I to put these in production. We would have to write the programs for the CNC machines and we would have to purchase a 7/8"-14 thread gauge set and set plug and a couple of 9/16"  and 3/4” reamers. We would also need to purchase a 47/64” and a 33/64" coolant fed solid carbide drill. The material could be purchased as surplus, as no heat No. and material certificates would be needed.

The prduction model would have to be built around whatever 100 lb. springs are available in quantity. I built the one I am describing around an extra spring that came out of a CNC turret lathe we had to work on a while back.

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Tom Acheson posted this 30 March 2014

Take a look at page 115 of the Lyman Cast Bullet Handbook, third edition. This is what my friend followed to make his units. There is a “window” on the side that takes some experimenting on your part to determine two points that need alignment. You do that a few times using a sample of pure lead. (See below)

Tip: you'll be measuring the diameter of an indent in your small sample. You need a good properly directed light source and us old fatrs (who can't spell) will benefit from some kind of magnifier to get the caliper anvils properly aligned with the outer edges of the indent.

The “window"........you cycle the press to see how far down the inner cylinder will go until you get a few repeatable pure lead readings, then you mark the outer sleeve. Then in all future readings, you depress the press's ram until the two lines are aligned and hold it there for 3-seconds .

My lead sample is a flat bar about 2"x 3” x 1/4” thick. I color each indent after measuring it so I don't mistakenly measure it again in subsequent trials.

It's kinda fun!

Tom

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John Alexander posted this 30 March 2014

There is no special procedure for submitting articles to the Fouling Shot.  Send the article along with any pictures to Glenn Latham, editor of the Fouling Shot (contact information inside front cover of the Fouling Shot.) Glenn is always looking for good articles and a good article about how to make a Brinell hardness tester would probably be of interest.   John

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Tom Acheson posted this 30 March 2014

If the photo stuck you get a general idea of what these look like.

This may not be the same the OP'er.

There is a line on the outsdie sleeve. You experiment until find where the inner cylinder should be to get an indent in pure lead of 0.154". That is the location all future samples should be read at. Follow the instructions in the Lyman book and it should work.

I too would like to see an article on this neat tool!

Tom

 

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mrbill2 posted this 31 March 2014

For those of us that would like to build are own tester we would need measured drawings. I dought many of us have CNC equipment. Thanks

 

 

NantachieRat wrote: I would be honored to publish an article about this in the Fouling Shot! How can we set it up? This would help fellow shooters alot.

The unit I built is just a basic prototype, but I can begin working on a production model. It would be no problem for my boss and I to put these in production. We would have to write the programs for the CNC machines and we would have to purchase a 7/8"-14 thread gauge set and set plug and a couple of 9/16"  and 3/4” reamers. We would also need to purchase a 47/64” and a 33/64" coolant fed solid carbide drill. The material could be purchased as surplus, as no heat No. and material certificates would be needed.

The prduction model would have to be built around whatever 100 lb. springs are available in quantity. I built the one I am describing around an extra spring that came out of a CNC turret lathe we had to work on a while back.

mrbill2

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NantachieRat posted this 31 March 2014

Here is the first of the photos of the http://castbulletassoc.org/forum/edit_post.php?id=75652#>hardness tester

 

 

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NantachieRat posted this 31 March 2014

This is a photo of the harness tester taken apart. The ball tip on the plunger was made on a CNC turret lathe, the rest on an engine lathe. The hex on the plug was made on a Bridgeport mill. The spring is one I found in the shop and I lucked out that it happened to be a 100 lb spring. A ball bearing could be soldered onto the tip instead of turning a ball tip.

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NantachieRat posted this 31 March 2014

I have AutoCad and I am going to work on a cut-away drawing of the entire unit and a drawing of each part. Everything will be dimensioned. This will be a time consuming proscess, but when I am done I will post it in PDF format.

I may rework the body by milling a flat on one side and then milling a 3/8” or 5/16 slot to provide a window like the unit pictured above. I will cast some samples tonight and see if I can adjust the depth of the body to just before the spring and plunger bottom out. I may have to shorten the plunger and body. It will be no problem to turn another ball tip as the program is already written. I will also try to make a lock nut like the ones on RCBS dies. Locking the set screw should set the position of the body in relation to everything else.

Initial tests with 1 lb ingots shows much promise. I am thinking about using a heavier spring to make a larger indent and using the standard Brinell hardness formula instead of comparing the results to pure lead. As I mentioned above, a 10 mm ball penetrator is the industry standard for Brinell hardness testing.

I am also going to begin working on an article for the Fouling Shot.

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NantachieRat posted this 31 March 2014

I have been wanting a Lyman 311299 bullet mould for some time, if someone has one to trade I will make them a hardness tester for an even trade.

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NantachieRat posted this 03 April 2014

This is how the hardness tester works. I changed to a 140 lb spring to make a better indentation. The sample on the left is my bullet alloy and the sample on the right is pure lead. The lead samples measure .200” the bullet alloy sample measures .114"

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4570sharps posted this 02 October 2016

Good looking tool!

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