Can someone explain how modern die rotations occur?

LanLord

I didn't want to hijack the SMS nickel post to ask this so I started a new thread.

This has bugged me for some time. I have a picture in my mind (perhaps incorrectly) that a die would have a "centering pin" something that will prevent it from seating at the proper depth until it has been rotated into the correct alignment with the press. If this is so, how could any modern coin ever be pressed with out of alignment dies?

Is it up to the press operators to review the alignment of dies? If so, I would expect more die alignment problems to occur as their QA doesn't seem to be all that great in other areas.

Thanks for any feedback.

keets

the mint worker can either not lock the die in tight enough, in which case it rotates slightly in the press, or else he installs it 180 degrees off to start. someone posted a while back that they started making the dies so they can only be inserted into the press in one way. with most of the die work i've done for plastic injection there's a flat on the dies for tightening with one or more set-screws. i would assume it's the same principal.

al h.

Conder101

There is a flat ground onto one side of the cylindrical die body. If this flat is ground in the wrong place the die face will be rotated from its normal position when the die is placed in the press. Other ways a rotation can occur is if the set screw that locks against the flat works loose then the die body can rotate. Third way is for the neck of the reverse die to break off of the die body. It will be retained in place by the collar and striking can continue but the die neck is free to rotate in the collar.

jonesy

When a worker places the die in wrong, you get this!!