Planchet question.

RobertLahti

Proof planchet?
Could I assume squared rims would narrow motive of why a wide rim planchet was stutter struck twice in a collar based on minimal clearance?

JBK

"Stutter struck"? Thats a new one for me.

In any case, as far as I know proof planchets are the same as other planchets except that they are polished. The squared rim of a proof coin comes from being struck twice under higher pressure.

The edge of your coin looks to me like it was perhaps flattened/squared by mechanical means, such as from being caught in a rotating machine.

Kliao

@JBK said:

In any case, as far as I know proof planchets are the same as other planchets except that they are polished. The squared rim of a proof coin comes from being struck twice under higher pressure.

Believe this is true.

I think that your coin was cut out of a mint set as the slightly thicker planchets look like what I've seen out of mint sets.

Don't quote me on this but I heard somewhere that coins for newer mint sets are struck at slightly higher pressure than business strike coins?

RobertLahti

I just know there are errors known as business strikes on proof planchets.
And proof strikes on business planchets.

Kliao

@RobertLahti said:
I just know there are errors known as business strikes on proof planchets.
And proof strikes on business planchets.

Taken from error ref:

Such an error is only detectable when the composition of the proof version is different from the business strike version.

https://www.error-ref.com/proof-strike-on-a-business-planchet/

jmlanzaf

@Kliao said:

@JBK said:

In any case, as far as I know proof planchets are the same as other planchets except that they are polished. The squared rim of a proof coin comes from being struck twice under higher pressure.

Believe this is true.

I think that your coin was cut out of a mint set as the slightly thicker planchets look like what I've seen out of mint sets.

Don't quote me on this but I heard somewhere that coins for newer mint sets are struck at slightly higher pressure than business strike coins?

That change occurred after 1997,I believe. It's only been in the last 5 years or so that the Mint has made that claim.

MarkW63

I've never heard of a "Proof Planchet" Its my understanding that all the planchets are cut from the very same GIANT roll of metal sheeting.
To my knowledge the mint doesn't buy small rolls of special sheet metal especially for Proofs, and LARGER rolls of it for business strikes.
Am I wrong?
The image below is from the US mint showing a giant roll of sheet metal that's about to be cut into planchets, that will then be struck to produce coins.

LanceNewmanOCC

@RobertLahti said:
I just know there are errors known as business strikes on proof planchets.
And proof strikes on business planchets.

.
do you know any reference that makes this claim?

MarkW63

In my post above that giant roll of sheet metal is feed into a high speed punching machine that cuts what is known as "Planchets" (little metal disk).
The cut planchets then are feed on to a conveyor that move them along until they drop out into large bins.
I don't know anywhere in the process where the mint would be having special proof planchets made. If there is then that is information I'd like to have?

Kliao

@MarkW63 said:
In my post above that giant roll of sheet metal is feed into a high speed punching machine that cuts what is known as "Planchets" (little metal disk).
The cut planchets then are feed on to a conveyor that move them along until they drop out into large bins.
I don't know anywhere in the process where the mint would be having special proof planchets made. If there is then that is information I'd like to have?

The only difference I can think of is the high polish and cleaning that proof planchets get before striking.

FlyingAl

@Kliao said:

@MarkW63 said:
In my post above that giant roll of sheet metal is feed into a high speed punching machine that cuts what is known as "Planchets" (little metal disk).
The cut planchets then are feed on to a conveyor that move them along until they drop out into large bins.
I don't know anywhere in the process where the mint would be having special proof planchets made. If there is then that is information I'd like to have?

The only difference I can think of is the high polish and cleaning that proof planchets get before striking.

This. Proof planchets get a high polish and cleaning before they are struck.

MarkW63

So, we're down to proofs are made from the same planchets that are giving extra prep (polish and cleaning) before they are struck as proof coins.

lilolme

Proof Coins: Making Money Episode 7
.
https://www.youtube.com/watch?v=LZMAY-53a-A

CaptHenway

Can't answer any of the above questions, but I do know that in the late 1960's, when the SFAO was making at first Special Mint sets to the standards later used for the 1968-S Proof sets, and then the actual Proof sets, some planchets were rejected for the Proof coin program, and perhaps for the 1967 SMS sets.
In 1968 through 1970 the reject five cent coin planchets were struck as business strike nickels in San Francisco. In 1968-1974 the reject one cent coin planchets were struck as business strike cents in S.F. All other reject planchets were dumped in steel barrels and shipped to the Denver Mint to be struck as business strikes. This was how we ended up with some 40% silver half dollar and dollar planchets being struck in Denver.
Planchets might have been rejected either before or after they were "Proofed." If a planchet that had been "Proofed" but was then rejected ended up being struck off center in Denver, or in S.F. as a business strike cent or nickel, you could prove that you had a business strike on a Proof planchet.
If one of those ordinary business strike cent or nickel planchets accidentally got struck as a Proof, I am not sure if you could tell.
TD