Bronze Ball? No longer a mystery.

[mikusek]

I found this in North Central Iowa on a slope just west of where an old farmstead used to be. At the time, there was still a pump standing. In the immediate area where I found this object, my Dad and I had found several small celts over the years, also several coins from the 1800's in the area where the house/yard probably was located.

This object is 1 3/4 inches diameter, it appears to be solid brass or bronze, it is heavy. I haven't weighed it. It has several dents. There are no makers marks or lettering. I have shown it to several archaeologists, no one could identify it with certainty, maybe I should have sought out a historical archaeologist.

One said he thought it was a ball for a small bore rifled cannon, the others had no idea. There are no rifling marks on it. He said he couldn't confirm his opinion.

John

Thanks to olroy70, TheCannonballGuy, & bigcypresshunter for the answer.

 

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[TheCannonballGuy]

Re: Bronze Ball?

Definitely not a cannonball. First, its diameter does not match up with any cannonball, Grapeshot-ball, nor Canister-ball in the historical records. www.civilwarartillery.com/shottables.htm

Second, brass, bronze, and copper, etc, are enormously more expensive metals than iron. There is no economic sense at all to use those costly metals for a cannonball. It makes even less sense when you calculate that (unlike the many other kinds of metal balls) a cannonball only gets used a single time.

Now, about what your brass/bronze ball might actually be:
A "good economic sense" reason for a ball to be made of a different metal than iron is when the ball will get used more than once AND iron is "unsuitable" for the job the ball will be doing. Some examples which meet both of those criteria are a well-pump counterweight ball and a pulverizer-ball. Iron gets rusty but brass/bronze/copper doesn't, and iron can cause a spark but brass/bronze/copper cannot.

To save money in making non-rusting balls and non-sparking balls, instead of making a solid brass/bronze/copper ball, an iron ball would merely be coated with a layer of brass/bronze/copper. If you can get the ball weighed on a jeweler's scale or a precision Postal Shipping scale, and report its very-exact weight, I can tell you whether you found a solid brass ball or a "coated" iron ball.

 

[mikusek]

Re: Bronze Ball?

I will have it weighed and let you know. Thanks.

 

[olroy70]

Re: Bronze Ball?

the bottom of a windmill uses bronze balls to allow the pump to work.

That is what that is! Bronze, because steel would rust. it was used as a check valve. each pump had 2!

 

[Bigcypresshunter]

Re: Bronze Ball?

I would think an older type one-way or check valve such as for a well pump could use a ball.

 

[mikusek]

Re: Bronze Ball?

A check valve sounds like it could be the answer, the pump had been removed by the time I found the ball. If that is what it is and they broke the pump, it could have fallen out. I forgot to take it with me today for weighing, it will have to wait for Monday now. I am interested in finding out if it is solid or clad.

 

[olroy70]

Re: Bronze Ball?

it is probably solid. most were, and designed to wear. They used leather for the water tight seal, and had to be replaced every so often.

One was on the pump, and the other on the bottom of the casing.

Fixing windmills was pretty bad for me, because, being raised in the flat lands of west Texas, a windmill tower was real tall......

olroy

 

[mikusek]

Re: Bronze Ball?

Definitely not a cannonball. First, its diameter does not match up with any cannonball, Grapeshot-ball, nor Canister-ball in the historical records. www.civilwarartillery.com/shottables.htm

Second, brass, bronze, and copper, etc, are enormously more expensive metals than iron. There is no economic sense at all to use those costly metals for a cannonball. It makes even less sense when you calculate that (unlike the many other kinds of metal balls) a cannonball only gets used a single time.

Now, about what your brass/bronze ball might actually be:
A "good economic sense" reason for a ball to be made of a different metal than iron is when the ball will get used more than once AND iron is "unsuitable" for the job the ball will be doing. Some examples which meet both of those criteria are a well-pump counterweight ball and a pulverizer-ball. Iron gets rusty but brass/bronze/copper doesn't, and iron can cause a spark but brass/bronze/copper cannot.

To save money in making non-rusting balls and non-sparking balls, instead of making a solid brass/bronze/copper ball, an iron ball would merely be coated with a layer of brass/bronze/copper. If you can get the ball weighed on a jeweler's scale or a precision Postal Shipping scale, and report its very-exact weight, I can tell you whether you found a solid brass ball or a "coated" iron ball.

It weighs 1 pound 13.70 ounces on the scale at the Post Office.

 

[TheCannonballGuy]

Re: Bronze Ball? SOLVED

Mikusek, I have to say I am amazed to hear that your copper (or copper-coated) 1.75"-diameter ball weighs 1 pound 13 ounces. It is about double the weight I was expecting to hear ...because a 1.75" IRON ball weighs approximately 13 ounces -- which is less than half of what your ball weighs! Also, a solid-copper 1.75" ball weighs approximately 1 pound 1/2-ounce ...which is 45% less than your ball.

Therefore, your ball is definitely a copper-coated one ...and the metal inside it under the copper coating (or, "jacket") is an extremely heavy metal, such as Lead.

Before I give you an explanation of my calculations, it is very important that you understand my calculation about your ball is based on your report that its diameter is 1.75 inches. Extra-precise measurement of a ball's size is crucial for figuring out what the ball is made of. If the measurement is not accurate, the calculations will not be accurate.

With that understood:
In case you are wondering how I made those calculations in regard to your metal ball.... my analysis is based on knowing about what is called the Specific Gravity "rating" of various metals. Rather than bore you with a long-winded, confusing, Technical explanation of Specific Gravity and the SG rating-number for various metals, I've give you just a short-&-simple explanation.

The Specific Gravity ratings are based on the Atomic Weight and "density" of various kinds of metals. An atom of gold weighs a lot more than an atom of copper.

To create a rating-scale for comparing the weights of different metals, scientists use a particular "volume" of the substance ...such as, one cubic inch (a cube which measures 1" on all of its sides).

For example:
In the Specific Gravity rating scale:
a cubic inch of water is rated at 1.0
a cubic inch of cast-iron is rated at 7.03 to 7.13
a cubic inch of copper is rated at 8.8 to 8.95
a cubic inch of lead is rated at 11.34

http://metals.about.com/gi/dynamic/...ww.reade.com/Particle_Briefings/spec_gra.html

Put in simpler language, what it means is, lead weighs 11.34 times more than water. Therefore, a 1"-diameter ball of lead will weigh 11.34 times as much as a 1"-diameter ball of water.

Also put simply... your 1.75"-diameter ball weighs twice as much as a 1.75"-diameter ball made of solid copper, so it absolutely cannot be a solid copper ball.

 

[Kieth-Tx]

Re: Bronze Ball? SOLVED

Agree about the weight issue. My calculations on a copper sphere (brass is lighter) would total- .90075 lbs or a little less than a pound.

http://www.precisionballs.com/ball_weight_and_density.html

 

[Ramitt]

Re: Bronze Ball? SOLVED

I appreciate your detailed explinations CBG.

 

[TheCannonballGuy]

Re: Bronze Ball? SOLVED

I forgot to include a link to the Specific Gravity chart in my prior post. I've now added it into that post... but here it is again, for anybody who already read that post and won't be re-reading it.

http://metals.about.com/gi/dynamic/...ww.reade.com/Particle_Briefings/spec_gra.html

 

[mikusek]

Re: TheCannonballGuy

Thanks, here's another photo of the ball with a vernier caliper. The postal scale was a digital readout, so the weight should be correct.

Would a lead center enable the weight and size to calculate correctly?

Thanks, John

 

[mikusek]

Re: Bronze Ball? SOLVED

Also put simply... your 1.75"-diameter ball weighs twice as much as a 1.75"-diameter ball made of solid copper, so it absolutely cannot be a solid copper ball.

Any idea how they would have either filled the brass/copper ball with lead, or coated a lead ball with brass/copper? I inspected it with a loupe, I don't see a fill hole that has been brazed, although there is one circular area about 1/4" diameter that looks slightly inconsistent with the rest of the surface. I also see a shallow hairline crevice/seam that appears here and there in what could be an equatorial line. Its too faint to photograph with my digital camera.

 

[Bigcypresshunter]

Re: Bronze Ball? SOLVED

Also put simply... your 1.75"-diameter ball weighs twice as much as a 1.75"-diameter ball made of solid copper, so it absolutely cannot be a solid copper ball.

Any idea how they would have either filled the brass/copper ball with lead, or coated a lead ball with brass/copper? I inspected it with a loupe, I don't see a fill hole that has been brazed, although there is one circular area about 1/4" diameter that looks slightly inconsistent with the rest of the surface. I also see a shallow hairline crevice/seam that appears here and there in what could be an equatorial line. Its too faint to photograph with my digital camera.

I was always wondering how they got the pot metal inside my gold plated jewelry? I would imagine its coated/plated.

I see the green check but I think it would not be check valve if its lead but I am not really certain. . Maybe olroy knows.

Now I am wondering what it is. An early full metal jacket? The hairline seam would be the mold mark.

 

[mikusek]

Re: Bronze Ball? SOLVED

I see the green check but I think it would not be check valve if its lead but I am not really sure. .

Is it possible to remove the green check?

 

[Bigcypresshunter]

Re: Bronze Ball? SOLVED

I see the green check but I think it would not be check valve if its lead but I am not really sure. .

Is it possible to remove the green check?

Yes. I think you can change it to a question mark.

CBG, what is it?

 

[mikusek]

Re: Bronze Ball? Still a mystery? surface looks like copper where caliper scratched

I think the hairline shows in the photo with the caliper.

 

[TheCannonballGuy]

Re: Bronze Ball? Still a mystery? surface looks like copper where caliper scratched

Mikusec wrote:
> Would a lead center enable the weight and size to calculate correctly?

No. I used the formula given at the website posted by Keith-Tx to calculate the weight of a solid lead ball whose diameter is the same as yours (1.75-inches). According to that formula, a 1.75"-diameter solid lead ball weighs approximately 1 lb. 2.3 ounces. So, your ball (at the 1 lb. 13.7 ounces you reported for its weight) is about 63% heavier than a lead ball of the very same size!

That is a shocking calculation. Forgive me, but it causes me to have to ask, are you absolutely certain you didn't mis-read the scale at the post office? Could it possibly have said just 13.70 ounces, instead of the 1 pound 13.70 ounces you remember it saying?

Another reason I'm asking you that question is that a 1.75"-diameter copper/brass/bronze "clad" cast-iron ball would weigh "in the neighborhood of" 13.7 ounces.

If your 1.75"-diameter ball actually does weigh 1 pound 13.7 ounces, we'll have to consider some of the (very few) metals which are 60%-to-70% heavier than lead.

There is a simple test which I should have asked you to do before now. Check the ball with a strong magnet, and let us know whether you feel even a slight "pull."

 

[mikusek]

Re: Bronze Ball? Still a mystery? surface looks like copper where caliper scratched

The best I can do is a simple balance comparison tonight, it weighs close to what a roll of nickles and a roll of quarters weigh, probably not too accurate though. I tried it against a 20 oz bag of dry beans and the ball is much heavier. Since my wife doesn't like bathroom scales........ none in the house.

No attraction to a magnet at all.