Loss of thickness in letters and numbers?

[mrmike916]

Just currios what would cause numbers or letters to lose some of their thickness? The T in Trust looks like it has some abrasion doubling and is thinner in the middle. Also the 1 starts thick at the top and narrow at the bottom.

[georoxx]

As dies age, they accumulate debris in the devices. Grease, mainly. This accumulation of grease makes the minted device smaller on the coin. (Less room in the crevises for metal.)

-George

[coppercoins]

Actually this is not the cause of what is shown in the images.

What you see in the images is caused by die polishing to remove clash marks and other die damage such as gouges. All details on dies are set up in a beveled fashion - thicker at the bottom, thinner toward the top - so the coin will pop out of the die when minted. Think of 'loaf pan' and how the bread pops out of the loaf pan because the pan is smaller at the bottom than at the top. Devices (letters and numbers) on dies are the exact same thing in much smaller form.

When you take field away from a die, the devices get polished upward from the thicker part to the thinner part. The result is what you see. Thinner than normal device profile.

[georoxx]

Actually this is not the cause of what is shown in the images.

I was more or less answering the generic question, "Just currios what would cause numbers or letters to lose some of their thickness?"

Thanks for pointing out the specific cause on this coin. (I didn't even look at the thread pic, to be honest. My bad.)

-George

[mrmike916]

Thanks guys!

[coppercoins]

George - because grease and other debris will fill a die cavity from the bottom to the top, the thickness of devices is not affected - only the height (or relief) of the devices because the thickest part of a device is going to be at the top of the die...the point where grease filling would make the device disappear altogether.

The question was specifically about devices that are thinner than they should be. Grease would be a very unlikely answer.

[georoxx]

Thanks again, Chuck. I appreciate your tutelage.

-George

[Maineman750]

I think this one one of the first questions Chuck ever answered for me....different place and time...but it made sense given that the devices are tapered... similar to a cake pan.

[Arjohn]

Think of 'loaf pan' and how the bread pops out of the loaf pan because the pan is smaller at the bottom than at the top. Devices (letters and numbers) on dies are the exact same thing in much smaller form.

Class in session and Thank You!

[coop]

Is it this year?

[mrmike916]

[QUOTE=coop;227257]Is it this year?
Looks similar, but its at 62 coop!

[coppercoins]

That is an interesting point, though. I seem to see these a lot more on 1961, 1962, 1963 and 1968 than any other years.