A problem with "brittle" nickels

[brandm24]

Portions of correspondence from the National Archives in regard to these brittle nickel 5-Cent coins was recently published by the Newman Numismatic Portal at Washington University in St. Louis. The correspondence tells of the problem of incorrectly annealed copper-nickel planchets used by the mint to strike nickels. Interestingly, the problem occured periodically from 1887 to 1896...an amazingly long period of nine years. Why so long to finally correct the supposed vendor problem, or was there a mint-deficiency  that they weren't willing to discuss? Easy to blame a vendor isn't it? See here.https://nnp.wustl.edu/blog-post/524281

Bruce

[Figleaf]

The text is unclear on what exactly "brittle" means, but I'll speculate anyhow.

Around 1900, the Brussels mint had a problem. They had introduced coins in copper-nickel, a new alloy. The second generation of these coins, 5, 10 and 25 centimes were struck until 1930. Today, these coins are often found with errors, due to flaking. On a flaking coin, a thin part of the surface will become loose during the coining process. Sometimes, the flake is folded double even before the flan gets into the press. The effect is strange, but immediately visible. Apparently, quality control did either not pick out these errors or did not care about them, as they are found relatively often.

The consensus among collectors is that flaking was caused by unequal mixing of the alloy. As the two metals expand and contract at different rates, flaking could occur at any step in the process of coining where heat was used.

Couldn't this problem have occurred in other mints also?

Peter

[brandm24]

The term brittle was meant to describe the actual breaking or shattering of the coins under certain circumstances.

The series of nickels before the Liberty Heads were known as Shield Nickels because of their design. They were minted from 1866 until 1882 and experienced numerous production problems. So many in fact that the mint nearly replaced them only a year after they were introduced. The intricate design and the hardness of the planchet (75% copper / 25% nickel) were to blame, apparently.

This was the first effort by the mint in striking coins containing nickel and they never got it right until many years later after numerous design changes and striking methods were tried. In the 1860's there was little thought of using nickel alloys in coin production. This all changed when industrialist Joseph Wharton lobbied endlessly for the use of the metal in coin production. Wharton, of course, had interests in nickel mining and production and was probably generous in his politicasl contributions...Imagine that!

I think we use the term delamination in place of flaking to describe the peeling off of layers of mental on a coin. The condition is quite common on US coinage and is blamed on improper alloy mix.

Bruce