"doubling"

[Dick]

Here is a bit of information, that I think will be of interest:
[quote]
Machine doubling can occur on any coin series, it results from parts in the press working loose from vibration during use. Tighten a few bolts and the machine doubling stops.

When the dies are first made all the letters do have the doubling but it is supposed to be removed during the basining/polishing of the die after the hardening process. My personal theory is that the doubling was intentional with its intent that it be used as a visual guide to let them know when the die had been basined properly. As the die was polished the doubling would be ground away. The mint worker could polish, stop and check for the doubling and see which areas still needed more work.

It could also be used to judge the hubbing process. When the doubling began to start showing up after a hubbing you knew you had impressed the hub deep enough and another hubbing would not be needed.

But they were often short on dies and so dies that had not had the doubling fully polished away were often pressed into service. This could result in doubling on some letters but not others. The doubling also fades away as the die wears or if it needs further polishing such as removing clash marks. All of these can result in the doubling only being on some but not all areas.
/quote]
I was not aware of certain things, until this was presented to me, and I thought it interesting enough to "borrow it from another forum, (CCF). This was in response to my question about Longacre doubling, etc, on FE, and IHC coinage.
Dick