Question on Hubbing

louis · New Member

I just received "Looking Through Lincoln Cents" and I immediately began reading. My question is:

Since a die (prior to 1997) required multiple presses and heatings, why were the dies not returned to the press with the correct/same hub for subsequent pressing to prevent doubling? Was it human error, lack of "paying attention to detail" or some other reason.

Thanks in advance to all who reply.............

eagames · Expert Member

My guesses...

They had no reason to use the same hub since they think they all are the same.

The same hub might get ruined so they use the new hub for the next hubbing. That way they get a DDO since the first hub was worn out and old then the next one is a fresh new one. It causes a shift to the center (new over old hub). On others they might mix a new hub in and then use an older hub second and those get a shift to the rim.

On some years they intentionaly used different hubs like on 1936 with the broken R they did one hubbing with the hub with a broken R then the second hubbing (or the reverse of this) with a different hub with a good R to fix it. They wanted to still get use out of the broken hub plus not have broken Rs.

Another funny year is 1941, they had a hub (or hubs) with broken Ts on TRUST and made lots of DDOs by mixing with non broken hubs.

Some years they changed designs (1960 or 1970 lg date & small date) and either kept both hubs for a while or had some dies in process of making when they changed hubs.

Then for some years they used the same hubs but by not aligning it perfectly they still made DDOs.

I'm sure there are other reasons, notice that in wartime they made more DDOs? (1917 WW1) or (1941 WW2) (maybe even 1971-72 Vietnam?) so the mints might have lost trained workers to the war service and new employees were being trained.

coop · Expert Member

Ed: I think his question was about the single squeeze dies. The ones with varities are not from multiple hubbing from 1997 (Or in that time) The single squeeze should have left one impression, but something must have faulted while hubbing or they started to hub and backed off and then hubbed leaving the center miss-shapened. (Don't know if that is a word or not??) The area from the first attempt made a distortion on the die and when squeezed the final time (Which they consider the first) the center of the die was pressed with a mark the hubbing did not remove in the center part of the die. As for why they didn't re-hub the die? I'm guessing they figured it would make problems as to the die would have to be re-made. Softening and hardening. So the hub was not at fault, the process was.

When they hubbed (the older process not of the single squeeze dies) you wonder why didn't they use the same hub? Consider this senario. The hubbing process involved time. Three days softening of the dies, pressing them. Well the same hub made several (Maybe hundred of dies made each day) Buy the time the second hubbing took place the hub wasn't the same hub. Why? Because of the wear usued on the first batch had worn down by the time it got to the second batch (later hub state) or was pressed with a different hub as the old hub may have been retired. When the hub wears, it makes the hub get wider with use. Image taking a screwdriver and putting it into clay. After hundreds of time you would notice little change on the impression the tip makes as the clay is soft and doesn't wear. But take the same screwdriver and smack it with a hammer on an anvil. After a few wacks and you start to nice a change in the screwdrivers tip. The metal to metal contact distorts the hub just a the coins distorts the die. It may be not as noticable as the hammer/screwdriver theory. But the hubs wear also and leave a weaker impression on the dies. Sometimes the same dies get used, but with age they leave a separation of the outer letters. Making some longer and other shorter with a new hub being used. We look for the separtion of the hubbing noticing the turn of the hub on the die, or the longer impression on the worn hubs to the die.
If I made any miss-assumptions here, I know someone will correct me.

louis · New Member

I think I get the picture.

Thanks again...............

coop · Expert Member

Welcome to coppercoins Louis. First time I noticed your name, but you have three posts.