Retained Cud Study - 1921-D VAM-1-H

Okay... Thanks Oz... That I suspect would all be true, (but highly misleading), and that is not the entirety of press set up..... What this refers to is initial set up of a press to strike Morgan dollars.

The dies are spaced to stop at predetermined points (giving a predetermined space or void between the two dies at strike).... Pressure is then adjusted by spring compression to a level that will bring up the devices in a test planchet..... After initial press set up, it is not readjusted on either a daily basis or when dies are replaced... It is set up (pressure wise) and will remain so until a different die design or planchet composition is introduced.

Pressure adjustment would be a long, drawn out process, performed by maintenance folks (not press operators) for long term reasons such as hard planchets caused by lack of sufficient annealing capabilities at the New Orleans Mint (for example).

Die set up controlled the spacing between the dies (based on planchet and desired coin thicknesses)....Pressure controlled the depth of die penetration into the planchet (based on planchet composition and hardness)..... Once initially set up, pressure was no longer a relevant issue in the striking of the coins..... The only thing that mattered was the spacing of the dies, and this was done either daily or whenever a die was replaced (whichever came sooner).

120 tons of unrestrained pressure (without proper die spacing) would result in a paper thin coin, completely obliterated dies, collar and and various press components simultaneously.

Liken the concept to a pair of adjustable pliers or vise grips... Your hand will exert a certain amount of pressure on the handles, but you might first think about adjusting the jaws to close at a specific gap between them to prevent crushing the item that you are applying this jaw pressure to..... the pressure exerted by your hand has not changed, but the gap between those jaws now is the only relevant controlling factor.

edited for spelling (is rather than in)

The definitive answer is no Gene..... Let me try to use different words about this.... If the dies are gapped so that the planchet is not even touched by the upper die, it does not matter if you have 120 tons of pressure or 500 tons of pressure.....the dies will not touch the planchet.

Consider this now....If the dies are gapped properly and the planchet hardness is correctly assessed, pressure will determine the depth of die travel into the planchet..... 50 tons might not be sufficient to bring up the design...... but 120 tons will bring up the design just fine...... tighten the springs to 200 tons, and the result will look just like it did at 120 tons, (because the preset die gap prevents the dies from closing any further).... thus the additional 80 tons is a moot issue, other than applying unnecessary stress on the press itself (overkill).

Yeah, I think that you've got it buddy.... but just to make sure, figure this out (don't give consideration to the dimensions, they are BIG to show relationships):

Say (hypothetically) that you are working at the Philadelphia Mint in early May, 1878...

(As a mint employee, you are aware that if pressure is sufficient to bring up the devices properly, the thickness of the coin field will come out to be 1/4")...You have been striking Morgan dollars for a month now, and are setting up a press that has been down for maintenance since 1877....

Say that the planchet is 1/2" thick....

You have properly set the dies to a gap of 1/4" at strike....

And, you do not need or want any more pressure than in necessary to bring up the design in the coin (to alleviate undue stress to the press), so.....

You set the pressure to about 50 tons, and strike.....but the design is very weak, and the test coin is thick at 3/8".....

You adjust the pressure up to 100 tons and strike.... the design comes up nicely, but it is not sharp, although the test coin thickness is correct at 1/4"....

You increase pressure some more, thinking that this should sharpen the strike..... the thickness is still 1/4", and the sharpness of the strike has not improved....

What is the problem?

It probably was not a very good question Mike.... (a bit tricky).

Sharpness of the strike cannot be increased by either pressure or gap adjustments.....

You, (the mint employee) installed worn dies in the press...

Let me ask a few questions (no tricks this time)....because I do not know the answers, but would be very interested in finding out....

What is the difference between Machine Doubling and Strike Doubling?

Are there still more different types of doubling other than what is found on the dies themselves?

Most importantly, does there seem to be a prevalence to machine/strike doubling in either weakly or strongly struck coins? On coins of certain years or mints? Does there seem to be a connection anywhere?

Hopefully someone will have an answer or two, since I think that all of you are fairly experienced at studying these coins.

I have also heard of a thing called 'ejection doubling'.... what is that? Is it predominantly only on the reverse or can it be on the obverse as well?

Thanks very much Mike.... I appreciate it.... I was really hoping that someone might know and reply.

Very good, but not entirely accurate in my opinion... I view the entire vertical assembly as a bar (not unlike a leg) the suspension rods as the femur, the toggle joint itself as the knee, tongue in groove pin assembly as the meniscus, the triangle as the tibia... the joint bends to raise the bar, and straightens to provide the snap or pressure.

I have had such miserable luck with getting my points across (even with the simplest of things), that I doubt whatever amount of time I might be inclined to invest in explaining this, that it would be even slightly understood or be of any interest... Since these pictures and diagrams only show the big stuff, let me say that there is a whole lot more to the press than just that... there are more little guts not shown here... so I will give this a one time shot, a very broad and basic shot....





Those things sticking up out of the top of the press are suspension rods... The bottoms of these rods are connected directly to the top of the toggle joint.

The part of those rods that are sticking up out of the top of the press are threaded.... the threads serve the purpose of holding two nuts on each rod... (why two nuts)? The bottom nut is used to raise or lower the rod as the nut is turned... the top nut is used to lock the rod in the desired vertical height position as determined by the lower nut.... (why raise and lower these rods)?

The rods (near the top of the press, just under the outer case), are encircled by very heavy duty springs.... The purpose of the springs ( in addition to shock absorbsion) is to increase or decrease pressure on the toggle joint as it snaps out of the bend... There are other things (not shown) that facilitate spring compression)....To a certain extent, it will also adjust downward travel of the entire bar.

The wedge is a single block of metal connected to the press (for stability) by three bolts, one each from above, fore and aft... its purpose is to prevent vibration and radical movement of the toggle joint by stabilizing the suspension bars as they are moved vertically by the toggle joint .... it is positioned between the two suspension bars that hold the joint...it sustains probably more wear than any other part on the press... easy access is attained for wedge replacement through removal of cover plates both fore and aft and the long bolt between the two rods from the top.....

Liken the wedge to the brushes on an electric motor... when they wear or break, things can quickly get rather erratic.

Imagine the press without the wedge..... collar clashes would be the norm, as the toggle joint would be flopping all around like a fish out of water.... A worn wedge will allow vibration and cause stuff like... (oh, I don't know)........strike doubling, perhaps? That is the only fashion in which I might consider that the wedge controlled the strike..... more accurately, though, the wedge controlled the image transfer (impression) from die to coin, not the actual strike.

What is this 'Longacre doubling' that I asked about on the classic coin variety & error forum (but got no answer)? Is there a good picture of it anywhere?

Where is this particular press located ?

It is my belief that the wedge would be more likely associated with Mechanical Doubling.... Spring compression is your pressure adjustment.... that is why I say that maintenance personnel performed this duty, not the press operator....his/her job would have been to keep the coin tube from running dry, and step on that clutch and scream when there was a problem.

I am dying to see an example of the Longacre thing as even your explanation in counter-intuitive to me..... the letters are normally peripheral devices...(on a convex die)? Logic tells me that the main devices would wear at an increased rate.

Do you have a picture of Longacre doubling Gene?