Denver Mint Die Shop

BuffaloIronTail

I haven't been able to figure this out. The Denver Mint can produce their own dies.

So..........does Philadelphia send them a die to copy for a new years coinage (like a new dime, etc.) so that the minted coins are identical by Mints?

Educate me, please.

Pete

dcarr

Philadelphia sends master hubs and/or working hubs to Denver.
Denver hubs their working dies. No engraving is done in Denver.

RogerB

I think - and not entirely sure - that Denver has a full suite of Micron die cutting engines. Philadelphia sends a digital file, and the dies are cut direct. Die cleanup is done automatically. There are no more hubs, master dies, etc..... But, this might be the "plan" and not actually implemented yet....The ol'e brain cells are frozen at present.

ricko

That is interesting... so, if a digital file contains an error, then there could be the same error from different mints?? Cheers, RickO

BuffaloIronTail

@ricko said:
That is interesting... so, if a digital file contains an error, then there could be the same error from different mints?? Cheers, RickO

It would have to be like that..........for the sake of "uniformity".

Pete

CaptHenway

@RogerB said:
I think - and not entirely sure - that Denver has a full suite of Micron die cutting engines. Philadelphia sends a digital file, and the dies are cut direct. Die cleanup is done automatically. There are no more hubs, master dies, etc..... But, this might be the "plan" and not actually implemented yet....The ol'e brain cells are frozen at present.

I am curious as to the cost of making individual working dies via cutting tools that wear out vs. hubbing.

dcarr

@CaptHenway said:

@RogerB said:
I think - and not entirely sure - that Denver has a full suite of Micron die cutting engines. Philadelphia sends a digital file, and the dies are cut direct. Die cleanup is done automatically. There are no more hubs, master dies, etc..... But, this might be the "plan" and not actually implemented yet....The ol'e brain cells are frozen at present.

I am curious as to the cost of making individual working dies via cutting tools that wear out vs. hubbing.

The main reason that mass-production dies are hubbed rather than machined/engraved is that a hubbing process only takes a couple minutes while engraving an entire die via CNC takes many hours.

The only US Mint production coinage dies that are not hubbed are the big silver "hockey pucks". Those are too big for effective hubbing. So each one is cut by a computer-numeric-controlled (CNC) engraving machine (in Philadelphia).

RogerB

I've watched working dies being cut by the Micron tools, but do not know if they were strictly test items or production. [I did not ask at the time.] The ones I saw were completely cut and finished for use within 10 minutes. Many could be made simultaneously and with nearly complete fidelity to the data file. Cutting a working die also imparts much less stress to the steel than pressing.

The "hockey pucks" are also manually cleaned.

Machine cutting tools wear no more quickly than hubs. In either case, a lot of attention has to go into getting it "right."

dcarr

@RogerB said:
I've watched working dies being cut by the Micron tools, but do not know if they were strictly test items or production. [I did not ask at the time.] The ones I saw were completely cut and finished for use within 10 minutes. Many could be made simultaneously and with nearly complete fidelity to the data file. Cutting a working die also imparts much less stress to the steel than pressing.

The "hockey pucks" are also manually cleaned.

Machine cutting tools wear no more quickly than hubs. In either case, a lot of attention has to go into getting it "right."

No, a die can not be cut in 10 minutes and be ready for use. The heat-treating (hardening) process alone takes several hours, at least, for heat up and cool down.

This Coin World article states that the US Mint indicates that a large 3-inch "America the Beautiful" die takes 5 to 6 hours to generate the CNC control file, and 16 to 20 hours to cut via CNC:
https://coinworld.com/news/us-coins/2016/11/mint-eliminates-step-in-3-inch-die-production.all.html

And after a CNC die is cut, it still requires some hand-finishing (about 4 hours) and heat-treating.

Hubs do wear out. Cutting bits also wear and/or the tip breaks off (the pointed tip is extremely small). Sometimes, the bit wears or fails before the cutting of one die is even finished.

Either way, yes, attention is required to get it right. Hubbing is actually easier (and much faster) than CNC engraving. The US Mint would hub the America the Beautiful dies if they could, but the diameter is too large for that to be effective. So the US Mint uses CNC milling for master hubs and large dies only.

ms70

@RogerB said:
I think - and not entirely sure - that Denver has a full suite of Micron die cutting engines. Philadelphia sends a digital file, and the dies are cut direct. Die cleanup is done automatically. There are no more hubs, master dies, etc..... But, this might be the "plan" and not actually implemented yet....The ol'e brain cells are frozen at present.

I think this is fascinating! Hopefully we will never be reading about N.K. or China intercepting the files.