Alloy BHN Calculator

Standard Member

CB posted this 08 January 2009

Nope, you are not doing anything wrong.

A forum member here discovered that the BHN calculation gave a slightly incorrect value. He demanded that it be removed as we were allowing incorrect info to go out to people.

Exact calculation is virtually impossible due to the fact that if you are using lead that is not virgin and if you do not know the exact percentages of the components in that alloy, you can not properly calculate using the calculator sheet. The hardness of that batch could and most likely would be off a little bit.

I found it close enough, but the fellow complained enough to get it removed and the one you have put in its place.

Sorry about that...

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JetMech posted this 09 January 2009

No problem. It's easy enough to do the math. In fact, given a little time, I can (with some help from my IT guy) make it work. I don't understand how it can give an incorrect value because the math is straight forward. It may be off a little due to complex interactions of the various elements during the alloying process, but for all intents and purposes, it's accurate enough. It's just a convenience when playing with ideas.

Thanks, Jeff

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joeb33050 posted this 09 January 2009

Jeff Bowles wrote: Nope, you are not doing anything wrong.

A forum member here discovered that the BHN calculation gave a slightly incorrect value. He demanded that it be removed as we were allowing incorrect info to go out to people.

Exact calculation is virtually impossible due to the fact that if you are using lead that is not virgin and if you do not know the exact percentages of the components in that alloy, you can not properly calculate using the calculator sheet. The hardness of that batch could and most likely would be off a little bit.

I found it close enough, but the fellow complained enough to get it removed and the one you have put in its place.

Sorry about that...

I'm the “forum member” who complained and demanded that it be removed. Jeff doesn't understand the relationship between the BHN and percentages of the alloy. It is a common mistake to assume that the BHN is the arithmetic mean = average of the BHNs of the constituents, proportioned, which is not true.

The attached graph is the only source I've found, and is from “Type Metal Alloys” By Frances D. Weaver, B.Sc. (Mrs. Harold Haywood), see: Journal of the Institute of Metals, Vol. LVI, 1935. The graph has been edited.

Certainly it is true that if one blends two metals or alloys which have quite similar hardnesses, then generally the hardness of the resulting alloy is similar to the average proportioned hardness of the two. Mixing BHN 12 and BHN 11 l-t-a alloys in 50% proportions will yield an alloy with BHN of ~ 11.5.

However, for Lyman #2, Linotype, WW, it doesn't work.

The complexity of a relationship should not be a determinator of it's acceptability.

joe b.

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JetMech posted this 09 January 2009

joeb33050 wrote: Certainly it is true that if one blends two metals or alloys which have quite similar hardnesses, then generally the hardness of the resulting alloy is similar to the average proportioned hardness of the two. Mixing BHN 12 and BHN 11 l-t-a alloys in 50% proportions will yield an alloy with BHN of ~ 11.5.

That is my point. The calculator is a useful tool. Although it is not exact linear relationship, for the puposes of the “average” caster, like me, it is sufficent. Rather than demanding that it be removed, it would have been more appropriate to explain the limitations of the linear method of determination and leave it up to the user as to whether it meets their needs or not.

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joeb33050 posted this 09 January 2009

Dollar Bill wrote: joeb33050 wrote: Certainly it is true that if one blends two metals or alloys which have quite similar hardnesses, then generally the hardness of the resulting alloy is similar to the average proportioned hardness of the two. Mixing BHN 12 and BHN 11 l-t-a alloys in 50% proportions will yield an alloy with BHN of ~ 11.5.

That is my point. The calculator is a useful tool. Although it is not exact linear relationship, for the puposes of the “average” caster, like me, it is sufficent. Rather than demanding that it be removed, it would have been more appropriate to explain the limitations of the linear method of determination and leave it up to the user as to whether it meets their needs or not.

The calculator as originally presented was incorrect, is incorrect, has no basis in fact and it gives incorrect results a substantial part of the time.

See the graph, compute your percentages, look up the BHN.

Let the user decide if he wants to use an incorrect method? Nonsense.

Many times in life there are not easy solutions. This is one.

joe b.

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Standard Member

CB posted this 09 January 2009

Bill,

The Alloy Calculator is a fantastic tool for most cast shooters who have an array of common lead products in their inventory. It will allow you to mix anything from pure lead to 25:1, wheel weights, Linotype, 50/50 solder, or a previous batch of #2Alloy; with mixing any of the combinations in a usable weight/batch for casting purposes, not scientific purposes.

Just a fantastic tool for those realizing its potential. It was never meant to be a Bhn Calculator...................Dan

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joeb33050 posted this 09 January 2009

Dan Willems wrote: Bill,

The Alloy Calculator is a fantastic tool for most cast shooters who have an array of common lead products in their inventory. It will allow you to mix anything from pure lead to 25:1, wheel weights, Linotype, 50/50 solder, or a previous batch of #2Alloy; with mixing any of the combinations in a usable weight/batch for casting purposes, not scientific purposes.

Just a fantastic tool for those realizing its potential. It was never meant to be a Bhn Calculator...................Dan

True.

The information, all the information, about this matter comes from “CAST BULLETSÃ¢â‚¬? by Col. E. H. Harrison.

The chart attached above is from “CAST BULLETSÃ¢â‚¬?, pg. 17 and again on pg. 131. We found 2 copies of the original article by Mrs. Weaver in the USA; one of which was at the University of Maine. John Alexander was kind enough to make and send a copy.

The erroneous notion that the weighted arithmetic mean of component BHNs = the alloy BHN has been accepted and published by several folks. This because it just plain makes sense. It just isn't true.

I hesitate to mention this, but I'm sure he wouldn't mind. On pg. 90 of “CAST BULLETSÃ¢â‚¬?, Col. Harrison himself makes the error in his response to “MAKING BULLET ALLOYSÃ¢â‚¬?

From “CAST BULLETSÃ¢â‚¬?

Pg. 87, the BHN of lead = 5, tin = ~7, antimony = ~50

On Pg. 78, the table gives the percentages of metals in various alloys, and the alloy BHNs

Using the BHNs of l-t-a above, calculate the weighted arithmetic mean of the alloys

Monotype, table BHN = 28, calculated BHN = 13.7

Stereotype, table BHN = 23, calculated BHN = 11.4

Linotype, table BHN = 22, calculated BHN = 10.5

Lyman #2, table BHN = 15, calculated BHN = 7.4

Electrotype, table BHN = 12, calculated BHN = 6.2

1:10, table BHN = 11.5, calculated BHN = 5.2

1:20, table BHN = 10, calculated BHN = 5.1

1:30, table BHN = 9, calculated BHN = 5.1

1:40, table BHN = 8.5, calculated BHN = 5.1

It is of some interest to note that actual BHNs are approximately half the table = ~true BHNs. I can't find an error in my calculations; invite others to set me straight. Perhaps it is true that for the smaller end of tin and antimony percentages, this “halfÃ¢â‚¬? approaches truth, but I can't get that from the graph.

joe b.

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JetMech posted this 09 January 2009

OK, Joe. I understand your argument. If you are alloying elemental metals to lead, the calculations are significantly off. On the other hand, if you are, like most casters, blending, say, 80 # ww with 20# lead, I believe the results are fairly accurate. I worked it out with lino mixed with lead and the calculated BHN falls in closely with what I have measured after actually blending the materials and hardness testing them.

On the other hand, if you were to, instead of using the given BHN of linotype, use the elemental ingredients in the calculation, it does not match.

So to me, for my use, I will simply drop tin and antimony from the chart and it will yield a usefull and reasonably accurate tool.

I think your problem is that you can not see the forrest for the trees.

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Standard Member

CB posted this 09 January 2009

Joe Before you assume what I do and do not understand you should ask, that way you dont end up looking like a fool and embarrassing yourself.

I gave the fellow what he needed to know, no more no less.

You chose to elaborate well beyond what was needed to explain and attack me in the process.

You can disagree and even argue your point, but I will not tolerate personal attacks. Do not make that mistake again.

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joeb33050 posted this 09 January 2009

Jeff Bowles wrote: Joe Before you assume what I do and do not understand you should ask, that way you dont end up looking like a fool and embarrassing yourself.

I gave the fellow what he needed to know, no more no less.

You chose to elaborate well beyond what was needed to explain and attack me in the process.

You can disagree and even argue your point, but I will not tolerate personal attacks. Do not make that mistake again. Jeff;

Do you understand it? It didn't seem so, after your sort of nasty comments about my actions. Are you allowed to make personal attacks? Because you're the webmaster? Please explain.

joe b.

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Paul Pollard posted this 09 January 2009

On the chart, is the BHN value the numbers on the right? How do we read the squiggly lines? What BHN value would it be if we had 3% tin and 24% antimony? Would it reach 32 BHN or would it never surpass 22 BHN, if it never crosses the wavy line?

Nice chart, but scant directions for using it.

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Standard Member

Lillard posted this 09 January 2009

Paul Pollard wrote: Nice chart, but scant directions for using it. I agree.

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joeb33050 posted this 10 January 2009

Paul Pollard wrote: On the chart, is the BHN value the numbers on the right? How do we read the squiggly lines? What BHN value would it be if we had 3% tin and 24% antimony? Would it reach 32 BHN or would it never surpass 22 BHN, if it never crosses the wavy line?

Nice chart, but scant directions for using it. The BHN values are the squiggly lines. Take the line marked “20” for example. Way up top left an alloy with 24% antimony and 2% tin BHN = 20. As antimony percent is reduced a lot, and tin percent is increased a little, BHN stays 22, see antimony % = 10% and tin % = 4%. Now the BHN 20 line squiggles some, ends up over on the right side where antimony ~7% and tin 14%. BUT, a bit to the left, at the dip down, BHN = 20 when antimony ~7% and tin ~7%. Add a lot of tin and BHN remains the same.The squigglers are in 2BHN steps, 10, 12, 14... and so on, so one must interpolate between the lines, for BHN17 for example. On the left side, with tin = 0%, it looks like antimony ~9% would = BHN of 17.

If that isn't clear, tell me and I'll try again.

I don't have any idea why the graph is tilted to the right, and the original graph and those in “CAST BULLETS” are more complex and confusing. I think I attached an original, the one above is, I hope, much clearer.

It is clear to me that the relationships are anything but linear.

joe b.

If I could find a clearer or more recent source, then I'd be happier with the data.

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Paul Pollard posted this 10 January 2009

Thanks, Joe.

The new chart with instructions does make it clearer on how to use it.

This might be a good money saver, since adding antimony without much tin will not give a higher BHN, as one would think. This chart looks like it will work if we can figure the tin, antimony, and lead percentages of the material we have. It may not have the elegance of a spreadsheet, but it does show a fixed relationship of the alloys. Think I'll make a copy of the chart and hang it over the casting bench.

Of course, after all this alloying, we get into the great debate of which BHN tester to use!

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Paul Pollard posted this 10 January 2009

I don't if this works on other computers, but on a MAC, I was able to click on the diagram and drag the diagram to the desktop and print it from there.

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John Boy posted this 03 April 2009

Being 'math deficient', what would be the Bhn formula for a Sn + Pb alloy for 1:11 and 1:14?

Using the calculator: 1:11 = Bhn 7.075 1:14 = Bhn 6.666

Why I'm asking - Back in the 1800's, paper patch bullets used for long distance shooting were cast in these alloy ratios. Today's times, casters and shooters of PP bullets keep saying use 1:20 and 1:30

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JetMech posted this 03 April 2009

John Boy,

That is the issue with the calculator. The calculator works well using mixing known alloys, but putting in tin, as an element, yields an incorrect BHN. While tin may hardness test at a BHN of 30 (or whatever is in the table), when alloyed with lead, the resulting BHN is not linear. Using Col. Harrison's table, 1:10, table BHN = 11.5, 1:20, table BHN = 10. So 1:11 or 1:14 would yield a BHN of about 11. A hair harder than 1:20.

As Dan Willems said “The Alloy Calculator is a fantastic tool for most cast shooters who have an array of common lead products in their inventory. It will allow you to mix anything from pure lead to 25:1, wheel weights, Linotype, 50/50 solder, or a previous batch of #2Alloy; with mixing any of the combinations in a usable weight/batch for casting purposes, not scientific purposes.

Just a fantastic tool for those realizing its potential. It was never meant to be a Bhn Calculator

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John Boy posted this 03 April 2009

Having an array of lead products, the calculator has served me well. I have found though, that when I am looking for a specific Bhn, particularly when using WW's, I pour an ingot from the melt - test for hardness and adjust accordingly. Thanks for the help "The Alloy Calculator is a fantastic tool for most cast shooters who have an array of common lead products in their inventory."

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Dale53 posted this 13 April 2009

If those who have a PC want to copy this chart:

Right click in the middle of the chart, pick “save image as” and save it to your place of choice on your computer.

The image is an attachment. To save the explanatory text, high light it and copy to your place of choice.

I opened a folder in my “Documents” labeled “Reloading data” and entered the chart and text separately.

Dale53

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Standard Member

krgottschall posted this 07 August 2009

Hi Joe, Thanks for the BHN chart:dude:

I'm new to this forum and to casting and I have been looking for a way to predict a BHN from percentages of tin, antimony and lead. I figured out it is not a weighted average of the components but was at a loss as to why.:( Your “contour map” chart explains a lot. :D I might be able to adapt this data into Excel look-up tables, allowing for interpolation errors. It would be helpful to know where the left side of the BHN 10,12 and 14 lines end at the edge of the graph and the route they took getting there.:) Wheel weights for example have 1/4 to 1/2% tin and 4% antimony. That puts the intersection in “no line” land.:shock:

I'll try to find the article this chart came from here in North East Ohio but if you know how the 10,12 and 14 lines should be finished, I would be grateful.

Although your chart explains a lot, it doesn't explain why the lines curve the way they do. Could it be heat? I know if you add a bit of arsenic to wheel weights you can heat treat them to 30 BHN. Any ideas?

Ken Gottschall

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CB posted this 08 August 2009

There are a couple of alloy calculator spreadsheets on the forum that may be of help.

http://www.castbulletassoc.org/viewtopic.php?id=3338&forumid=57&highlight=alloy+calculator

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calinb posted this 10 August 2009

Great chart! Now all we need is the same thing, but after heat treating to right below the solidus temperature. :) Sb and Sn are expensive so we really need to know alloy performance after the money-saving heat treating step.

There are some very interesting generalizations to be noted from the data. Below around 7% Sb (antimony), alloy hardness is relatively insensitive to Sn (tin) concentrations, and there's actually a region where adding more Sn lowers BHN To see this, note the how the contours dip to minimums along the 7% Sn line (contour axis) low in the graph.

As previously noted, high on the graph (high Sb concentrations) we find extreme sensitivity to Sn where the contours are steeply negative, indicating extreme BHN increase with Sn concentratio. Anywhere above 14% Sb, the more Sn, the better to increase BHN!

The closed contours aound 10-12% Sb / 11% Sn are just plain bizzare!

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CB posted this 10 August 2009

Bill

All good info for me a 47 yr Caster trying to make good bullets. Alloying has always been for me add more WW. I knew there was a correlation between lead vs everything else but always relied on my WW. I can do the math and enjoy this discussion.

Stephen Perry

Angeles BR:fire

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Paul Pollard posted this 09 June 2010

This dredges up an old discussion, but I played with the graph and put each intersecting point (1 percent) in a lookup spreadsheet. Where the lines on the graph are not complete, there isn't much to go on. For the rest of the graph, each tin and antimony intersection is listed with the BHN listed as close as possible.

My copy of Metals Handbook, 8th Edition, Volume 1, has a list of type metal alloys with their BHN listed. Those values match up closely with the graph listed in this thread.

My spreadsheet has an alloy calculator using my known alloys. It will calculate the new percentages and display the resultant BHN. It also includes some tables for calculating bullet weights from my moulds using my alloys. All of this stuff is automatic once you go through some hoops.

When I convert this mess to Excel, I'll post it here, if allowed.

This only lists lead-tin-antimony alloys. I have no idea about lead-tin alloys.

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CB posted this 09 June 2010

Paul you are welcome to share your info here, excel sheets can be uploaded as an attachment.

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krgottschall posted this 09 June 2010

One thing is not clear to me about “percentages". Are the Percentages by weight or volume? If they all weighed the same per a given volume, it wouldn't matter but they don't. Lead weighs .410 lb/cu.in., tin is .263 lb/cu.in. and antimony is .242 lb/cu.in.

In all my reading about bullet alloys, it seems that the reader is assumed to know what the percentages mean. My guess is that percentages are by weight because weight is easier to control than volume but I would like a definative answer.

I was able to get a copy of the paper that included the “contour line” chart of BNH's shown earlier. My hope was that it would also include the table of data points that were used to produce the chart but no such luck. The paper DID describe the methodology used to develop the data though. They simply mixed up a bunch of different alloys, measured the BHN of each and plotted the data on the graph.

It would be possible for anyone to replicate the process to fill in the missing area's of the graph if you have a Lee or some another brand of BHN tester, BUT one would need to know if the alloy percentages are by weight or volume.

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calinb posted this 09 June 2010

Nifty, Paul!

I've mixed up a few batches of alloys that span about half the space of the graph and I've found the BHN to correlate quite well to my Lee hardness tester. Certainly the correlation is good enough for the purposes of casting and shooting bullets!

Yes--the chart doesn't say much about alloys lacking antimony. There's no data along the lower boundary of the chart, but the only curves that appear close enough to the bottom boundary to possibly touch it (0% antimony) are the 10 and 12 BHN curves.

I'm looking at a hard copy table that includes the following entries. (I don't know its original source but it was obviously compiled from several sources of alloy data): Tin Antimony Lead BHN 2.5 0 97.5 8.2 (Handloader #183) 2.5 0 97.5 8.5 (Cast Bullets-E H Harrison) 3 0 97 9 (Cast Bullets-E H Harrison) 5 0 95 10 (Handloader #183) 5 0 95 10 (Cast Bullets-E H Harrison) 7 0 93 11.2 (Handloader #183) 9 0 91 11.5 (Cast Bullets-E H Harrison) 10 0 90 12.5 (Handloader #183) The Harrison and Handloader #183 data seems to be, essentially, in agreement. Overall, these values correlate to the lower boundary of the chart, inasmuch as the 10 BHN and 12 BHN curves end near the lower (0% antimony) boundary of the graph.

There is a slight miscorrelation between the graph and the above data. The graph tends to indicate decreasing BHN with increasing tin around the 8-10% tin point. The only physical explanation for the miscorrelation is other factors, such as temperature or impurities, may also affect BHN in the vicinity of this “unstable” region.

Regardless, at a very functional level, you may be able to interpolate between the points in the above data and extend your spreadsheet lookup space.

-Cal

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JetMech posted this 09 June 2010

krgottschall wrote: One thing is not clear to me about “percentages". Are the Percentages by weight or volume? I checked a couple Material Safety Data Sheets (MSDS) and the percentages there are listed as “by weight".

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calinb posted this 09 June 2010

Fortunately, the ones I posted are by weight. I've found it easy to dip the “sweetner” (a bar of tin) into the melt and measure its weight weight loss after melting some metal off the end of the bar.

Similarly, all of my hardness results have correlated to the graph by using weight.

-Cal

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Fairshake posted this 06 July 2010

I had a friend in CA. that told me he had gotten WW's there that gave a read out of 15 BHN when tested. The ones that I have gotten in Louisiana read 10BHN. When you are a caster in todays times you need a good tester to make your alloys so that the bullets you make will do the job they are intended for. Shooting bullets that are a 22 BHN at a cowboy match are dangerous and a waste of alloys. A BHN of 10 is more correct. I also prefer to use my Cabin Tree tester. I bought from a forum member on the Cast Boolits forum what was stated to be pure lead for my BP shooting. When it arrived I knew it looked wrong and tested out at 10.5 BHN. Buy a good tester so that you don't have to not know what you are shooting.

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Dicko posted this 21 July 2010

I have never understood the desire to over-complicate a simple thing. That BHN chart is excellent and the only tool you need. I have had it for years. Hardness testers are waste of money. The one I tested (won't say which for fear of getting sued) gave widely disparate readings on bullets from the same alloy. Hardness is precisely related to ingredient percentages, so why bother with unreliable hardness testers when all you need to do is blend the alloy accurately ?

OK, I note the argument that the ingredient percentages of some alloys eg wheel weights are unknown, but variances are closer than can be reliably determined with a hardness tester. In my experience, scrap lead can safely be assumed to contain 1% antimony and no tin. OK, WW seem to be the preferred raw material in the US. The standard spec is half % tin 4% antimony. I have tested some at 2 to 3% and have some limited confirmation of that in the US. How do I test them ? By casting bullets with the raw material, weighing 100 and comparing with weight of bullets of known alloy. How does that work ? SG of lead and antimony is very different, so weight of alloy varies according to % antimony. That is more accurate than a hardness tester. Lot of work for sure, but that's why it pays to cast in bulk lots.

Keep it simple, guys, scrap the hardness testers and rely on simple maths.

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CB posted this 22 July 2010

I use the alloy calculator now and then, I do have a industrial duty hardness tester out in my machine shop.

For me, I use common sense, trial and error plus many years of casting.

Most of the lead I find on the market is reclaimed from some source and of course range lead.

This is like the MOA discussions, I believe more in MOGH, Minute of Ground Hog.

I just cast up some 500 grain 50 caliber bullets that are close to 20 to 1 alloy. They go bang, the ground hog falls over. During deer season, I use my home cast shotgun slugs and “punkin balls". I find that casting them out of “WW alloy” is much better than pure lead. The shotgun goes boom, the deer falls over, just not as fast the ground hogs.

Bullet casting is an art as well as a science.

Jerry

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Alloy BHN Calculator

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