What is the difference between Open and Closer Collars?

jmcu12

In the Bust series there are Dimes, Quarters, and Halves that have both Open and Close collar strikes. I am not sure I understand the difference?

What does it mean?

BustHalfBrian

I know Bust halves (1807-1836) weren't struck in a collar at all - so I imagine this would be an "open" collar. Edge lettering was applied to the coins prior to them being struck.

"Closed" collars, I assume, are just like the collars that are used to strike coins today, that also apply reeding to the edge of the coins.

lkeigwin

An open collar positions the coin but does not disturb its edges which may have been set with edge lettering dies.

A close collar (aka, collar die) fits around the neck of the anvil/lower die and restricts the coin, during striking, to its size. It may be plain or grooved for reeds. The Mint started using close collars sometime in the late 1820's.
Lance.

jmcu12

Lance - thank you, that helps but I have a follow up.

If an open collar does not disturb or constrain the edge how do they control the diameter of each coin? Was that because of the striking pressure?

coindeuce

The Draped and Capped Bust halfs struck in open collar were actually constrained to the effect that the open collar controlled the final diameter to maximum 32.5 mm. Although the Draped and Bust type halfs were made on heavier planchets (13.48g) than the subsequent close collar issues of 1836 or later (13.36 g), the open collar issues were slightly thinner and larger non uniform diameter (32.5 mm, later reduced by close collar to uniform 30 mm.) Dimes were struck in close collar (reeded edge) earlier than halfs(1828). Quarter dollars first struck in close collar in 1831.

BustHalfBrian

<< <i>Lance - thank you, that helps but I have a follow up.

If an open collar does not disturb or constrain the edge how do they control the diameter of each coin? Was that because of the striking pressure? >>



Let me give this another shot;

The planchets were prepared with the expectation that, when struck, the metal will expand to apx. the intended diameter.

This why the diameter can vary a couple tenths of a millimeter between each coin that is struck. It was not an exact science in this era. As long as the weight of the planchets was correct, and the diameter of the coins was nearly correct, the coins would be released into circulation.

lkeigwin

<< <i>If an open collar does not disturb or constrain the edge how do they control the diameter of each coin? Was that because of the striking pressure? >>


Right. The planchets started with the same size. And you would expect that coin sizes would be similar due to consistent striking pressure. But there were too many other variables like planchet thickness and hardness, die orientation, etc. So these early coins varied in size a little. Even in shape. Sometimes a circle crop for an image doesn't quite work right.
Lance.

BustHalfBrian

<< <i>

<< <i> ...So these early coins varied in size a little. Even in shape. Sometimes a circle crop for an image doesn't quite work right.
Lance. >>



Yay, I was right for once

jmcu12

Ok that makes sense to me now. Thanks!

JRocco

This variation can be seen when trying to get CBH's into an album.
Sometimes it is quite an adventure to get these coins to fit.

Nysoto

As others stated lettered edge coins did not have a "close collar" to set the diameter of the coin, as any collar was "open," and may have been a centering device. Nobody knows for sure, because the early mechanisms do not exist.





<< <i>If an open collar does not disturb or constrain the edge how do they control the diameter of each coin? >>



With the "Castaing" machine, which applied the edge lettering, also "upset" or thickened the edge slightly. This also work hardened the edge, which helped to control the diameter. This is proven by some errors of bust halves without edge lettering, which are larger diameter and appear broadstruck (except for one unusual example). There was only a weight requirement, and not a diameter requirement, for early bust coins. Draped bust halves are slightly larger in diameter than capped bust halves, and all vary slightly in diameter. The DBH's are also a little out of round, with the diameter slightly greater from 12 to 6 than 3 to 9, because of the metal flow direction on the portrait.

The reeded edges of early bust coins were probably formed by a reeded collar at strike. This is proven by consistent reed counts that may suddenly change (because of a new reeded collar with a different count), and also by off-center strikes don't have reeded edges because they were out of the collar.

MrEureka

Earlier post deleted, but I will be back!

BustDMs

See The John Reich Journal Volume 26 Issue 1 April, 2016 pages 30-7.

Dismissing the Castaing Machine Myth.

You can access it on the Newman Portal if you do not have a copy of the journal.