1937-D 3 legged Buffalo...how?

[jackson64]

I was thinking recently on how it appears almost arbitrary which coins are considered rare error coins/varieties while so many others are ignored.The 37-D buffalo nickel with 3-legs, was it a filled area of the die,weakly struck, what?...it seems that some have more of the leg than others. If it is either weakly struck or a filled area of the die, it makes me wonder why it is considered an error and not just poorly struck.

What got me thinking on this line were the SBA dollars..type 1 and type 2's from 1979 & 1981. More accurately called clear S and mushy S. The type 2's are getting some serious bids in upper grades...however while sorting through some Mercury dimes, I found many dates with large and small mintmarks {get a handfull of 34-D's and look for yourself} also the location of mintmarks strays from near rim to almost touching the olive branch. I could list many more examples of unrecognized varieties/errors but again..my question was...what caused the 37-D to only have 3 legs?...ty Jackson

[Scott_Schechter]

From Walter Breen's Encyclopedia of U.S. and Colonial Coins: "A different blunder created the famous 1937 D Three Legs var. : excessive regrinding of a die to remove clash marks. Die clashing is a common accident at any mint: A tiny metal fragment or the like comes into the hopper among blank planchets, thence to the feeder - where it jams the mechanism and delays or prevents a planchet from reaching the dies. At which point, the dies, having no blanks to stamp, strike each other instead, often repeatedly, each leaving traces of their designs on the other. Routine procedure then is to stop the press, condemn and discard the dies which have become defaced by clashing, clear out the feeder, replace the dies with new ones and resume normal operations. At the time of the 1937 accident, the pressman (a Mr. Young), then a newcomer, was under pressure to complete a quota, so instead of replacing a pair of clashed dies he took an emery stick and ground off the clash marks, in the process removing the bison's foreleg and weakening many other details. These coins escaped into sealed sacks among normal ones, in quantity, before inspectors condemned the dies and many impressions."