21 D Die Scratch Or Crack Help

Yours is another plausible explanation, but there are (to me) weaknesses in it which equal the "hardness test" weaknesses.

If it were a hardness test, I could imagine a jig with a single cylinder of very hard steel, driven downwards by a spring of known tension. The depth of the impression it created on the die would indicate the relative hardness of the die steel. This might be a recommended practice, if you were in fact using steel from the South Carolina in your dies.

The '21-D VAM-3 is actually a rather nice example to throw out for discussion. I'm thinking the location of the "dot" was a rather poor choice, or a rather sharp one - if the die were weak at the intersection of the field and device, the die would not have much life before age caused the delineation to fuzz out.

Now, I'm forced to ask this based on my inferior knowledge of metallurgy: 1921-D VAM3 and its' sub-VAMs are not exactly rare on the ground. I've personally been through a number of VAM-3A's in progressive stages.

All have the "dot."

Would a bubble in the die have the strength to last through a relatively large number of strikings, including a progression of that huge wing break, while remaining perfectly circular with sharply-defined shoulders? Remember, these "dots" are very sharp, as sharply-shouldered and defined as any deliberate device.

SD, wouldn't your question apply to no matter what caused the incuse impression in the die?

It is my belief that the mint did not possess an actual steel mill (where it could take a steel plate from the starboard bulkhead, liquefy it, and remold it into a die), but rather acquired its stock from out of house (from somewhere like the steel mills of Pittsburgh).... I might further imagine that the mint might make requisition of a specific grade of steel (density) for the purpose of fabricating coin dies, but had little control over what was available or what it actually received.... (keep in mind, I am only daydreaming about everything I say here).

In my effort to further denounce the notion of a hardness test:

Whether the dot were a cause of spring loaded jig, or hammer and punch, I doubt that striking the vam-3 die in such a location could occur without slippage into the device or at least breakage of the drop off ledge.

If the intent of this test was to determine die hardness, I would think that it would be done after the die was hardened rather than before (when such an event could occur without risking stress fissures in the die surface).

If such a test were to be performed at a predetermined exertion of force (like the jig), I might think that care would have been taken to consistently strike either in the field or in the device, but not haphazardly, sometimes in a device, sometimes in the field, sometimes in the denticle.... (the anticipated goal is lost on me).... Cracks are caused in the die surface because the surface and edges of the die are the areas most subject to being brittle from annealing.... intentionally damaging this surface for the purpose of a test of immeasurable determination is beyond my scope of comprehension.

The small surface area of the dots (relative to the larger surface areas of devices, including mm) leads me to believe that wear (the possibility of round over of the drop off ledge) would be minimized as the load of the press strike would be spread out (over rather than into) the dot by the sheer expanse of its neighboring field or device.... I further might think that a dot in a device would weather the storm of striking better than one in the field because (relatively), the field is the initial impact zone, while the device collects planchet displacement at a lesser degree of compression, especially in an area between two opposing devices.

It seems logical to me that the devices in a die might already be a tad denser than the field anyway (from compression of hubbing), so the inconsistency of dots in the devices, dots in the field would negate any noteworthy conclusions as to the hardness of the overall die.

I have attempted to transfer my thoughts on why hardness testing is not the culprit.... and while I cannot detect any obvious flaws in my best guess notion of gas bubbles, I would very much like to hear what your best guess might be VfM (if you have even given this any thought of course).

Sorry Ceylon, I really didn't mean to run over you like that.... it looks to me like chip is a chip rather than a dot.

Bite your tongue, VfM.

Ceylon62, I gotta rack my brain (and VAMworld) to figure out which 1921 I'm thinking of with the dot between the lips. The location of your chip/dot is in the precise place I remember, but it's not mentioned in the 1DM description. I've asked for advice over there regarding it.

I am quite torn about the "dots." The argument against hardness testing - aside zeewool's very strong point that nobody in their right mind would put one at the junction between field and device - is that I feel the "sweet spot" for getting a proper strike on the die is very small indeed. Springs do not exert equal tension throughout their compression range, and a mechanical linkage similar to that which actually strikes the coin (the only linkage I can imagine capable of exerting enough force) would exhibit a similar "sweet spot." I think that the difficulty of jigging up such a tester, and the variance between individual dies, would defeat the ability to trust the test results.

On the other hand, zeewool's theory of die bubbles is argued against by the known (in Mint State coins) cylindrical shape of the "dot." There is a known, flat-sided, vertical component to the "dot," and the convex (on the coin) top has a clear, linear intersection with those sides. Uncharacteristic for a bubble. Also, if I have personally seen half a dozen of VAM-3, how many hundreds were struck, and would a bubble survive that long?

In honesty, this remains a mystery to me and one I'd dearly like to solve.

Oh, zeewool - the DeLorean is a reference the automotive star of Back to the Future, and VfM's desire to travel back to the time where a whole lot of these questions could be answered with finality.

Dave,
Thanks for posting it over there.

http://www.vamworld.com/Edgar_1921-...on_small.jpg I cannot get into this link. Does one need to log in?

http://www.vamworld.com/message/vie...1967#6422529 1CQ -- although they refer to the chip in front of the lips it does have one inside the lips as well...

http://www.vamworld.com/message/vie...9879#4693393 -- This one has the chip in the same location. Any idea what became of this one?


Not sure if any of the above lead anywhere....

Pardon my ignorance here... what exactly is a Hub Dot? (that is verdict per vw) Thanks

Zee, some of that is over my head and for the time being and I refrain from getting into the all the technical nuances. IF I can SEE IT.. then I am in.. Else it becomes an academic discussion which I am not suited for with my limited knowledge (but I do read and educate myself).