Hi Zo . Funnily enough as you may know I bought a 1922 dot on trident penny recently , and was having a really good close up look at the dot with the magnifying glass, only to discover a minute crack running from the teeth down along the right side of the centre prong of the trident . The crack is hard to see as it blends in with the scratching damage on the face of the die . This dot is of course circular and not elongated at all.
I had a count up of all the dot pennies and found that six are elongated , and show a crack running off or extremely close to the dot/comma. I've just three with almost perfectly circular dots two of which have a tiny crack running off the dot . The only one I have with no sign of a crack at all is the 1897 dot , but Freeman states that an example was found showing a tiny crack nearby . I don't have an 1870 dot or the cannon ball 1875 which look to be circular in shape.
My thoughts on the drilling of a hole at the end of a crack in order to stop it spreading would only work on a flat sheet , in this case the die is a deep block of metal , and a crack would run extremely deep down into that block , perhaps as deep as an inch [2.5 cm] or more, and it would seem to me that drilling down to that depth with a drill bit of 1mm or less would be near impossible . Any shallow drilled hole would be ineffective as the crack would continue to spread deep within the die
Picture Terry