Re: 1986-D Dime possible Rockwell test mark?
- A Rockwell hardness tester can be used on dies or planchets. When used on a die, a Rockwell test mark will appear as a pyramidal or dome-shaped bump. When used on a planchet, a Rockwell testmark will appear as a pyramidal or hemispherical pit.
Here we have a pit, but it's unlikely to be a Rockwell test mark because of its gently sloping sides. A Rockwell test mark will have sharply-defined borders.
When you really get down to it, it's almost impossible to distinguish a Rockwell test mark on planchets from circular or semi-circular struck-through errors.
The only verified Rockwell test marks on planchets come from cents minted in San Francisco in the early 1970s. I'm not aware of any verified examples in U.S.dies.
--- In email@example.com, innff@... wrote:
> If it were a "Rockwell" test, it would be testing the planchet hardness
> and not the die hardness.
> We do have this section in _www.error-ref.com_ (http://www.error-ref.com)
> that deals with "Rockwell" test marks on planchets. This is the link:
> In a message dated 6/14/2013 8:11:04 P.M. Eastern Daylight Time,
> jay4202472000@... writes:
> In photos I have created a "Rockwell" album for the pics. I have found a
> 1986-D Dime with an interesting "pit" between STATES and OF on the reverse.
> Is there any chance it is a Rockwell test mark? The bottom of the "pit" is
> smooth so it doesn't look like it was dug or scraped out. It may be PMD, but
> if it isn't what would have caused this other than a Rockwell test. I know
> this cause is highly unlikely. I just wanted to check it out. Thanks all!