Solid Copper Ball mystery

[jajayo]

My good friend Charlie was searching an area in Clarkdale, Az. This area was active from 1890's to 1950's. It served the miners of Jerome, the billion dollar copper camp, as a commercial district as well as some residences. Over the last two years we have found many small treasures in this area. He called me this day to tell me about a solid copper ball he found, so I was curious and asked him to bring it by and show me when he could. A couple of days ago he did and I was mystified. It was fairly cruddy with calcium deposits and dirt. He said he was going to clean it up and bring it back, which he did today. We can't figure it out so I surrender to you master sleuths out there for help.
The ball measures, precisely 1.3 inches in diameter, not a thousandth more or less and the weight is 5.5 ounces, not a gram more or less, we speculate it is solid copper but we did not drill it to see for sure.

 

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[pjduff]

A couple of years ago, the wife and I took a tour of the Queen Mine in Bisbee Arizona. One of the things we bought at the souvenir shop while at the queen mine was a solid copper ball, same dimensions and weight as yours. So that is a possibility, that it is something produced locally for the tourist trade.

 

[OWK]

Apparently these are produced in the Michigan peninsula.

While doing a quick search, I read that they are used as specimen pieces, and I also read that they are used as donor plating material.

Here is a link to an similar one on Ebay:

Native Copper Sphere Specimen 99 9 Michigan 30mm 123G | eBay

 

[Red James Cash]

The mexicans used copper cannon balls.

 

[vpnavy]

Actually, kind of neat - even if they may be souvenir! Thanks for sharing...

 

[Rick (Nova Scotia)]

cool.

the ebay one at 30mm is 1.18 inches just sayin'

 

[TheCannonballGuy]

Jajayo, the ball's finder, wrote:
> The ball measures, precisely 1.3 inches in diameter, not a thousandth more or less and
> the weight is 5.5 ounces, not a gram more or less, we speculate it is solid copper but
> we did not drill it to see for sure.

Jajayou, I see you are new member, so... welcome to TreasureNet, the best place on the internet to get objects CORRECTLY identified.

The super-precise diameter and weight measurements you gave us prove scientifically that the ball is a copper-plated iron ball. You say it is 1.3"-diameter and it weighs exactly 5.5 ounces. According to the precise data in the Canister-balls chart here:
Cannon bore, shot, and shell diameters for smoothbore guns
a 1.33"-diameter ball made of solid cast-iron weighs .32-pound (5.3 ounces) -- almost exactly the same as your ball.

According to the Specific Gravity Of Metals data here:
Solids and Metals - Specific Gravities
copper is about 25% heavier than cast-iron, so if your 1.3" solid (not hollow) ball was made of nothing but copper, it would be about 25% heavier than an iron ball which is the same size. But it weighs very nearly exactly the same as a 1.3" cast-iron ball, so it HAS tyo be a copper-plated iron ball.

Copper-plated iron balls are often used as the check-valve ball in a water pump. It is copper-plated for two reasons:
1- An iron ball would become encrusted by rust from exposure to the water, preventing it from forming a good seal in the pump.
2- It is merely plated with copper because copper is a much more expensive metal than iron... using a solid-copper ball would be unneccesarily expensive.

See the diagram showing a pump with a check-valve ball, below.

 

[jajayo]

The ball is not magnetic, so it must be hollow according to the weight chart. We will not be cutting it in half to find out. thanks for all your input.
I have been a member for at least six to eight years now and have posted here before, but rarely. Thanks for the welcoming anyway.

 

[coinman123]

Pretty neat find!