Quoted from TimeBandit:The problem with all this is it doesn't appear you have determined what a change in hardness means to the size of a dimple. I have just done some messing with the formula and found that on a scale of HB from 140 to 200, the effective change in dimple size is from about 4.2mm to 3.5mm. So, on the basis of your hardness numbers alone, across the entire universe of your tests, the dimple size variation with hardness is a maximum of 0.7mm (1/36 in) diameter.
This is certainly not visible to the human eye across all the different types of dimples on all the different playfields.
The range was from 90s to 190s I think, I'll have to take a look. Im also not sure what conversion you are doing, but if you figured some way to equate a number with a size than that's a good reference point for people. keep in mind, as I said above, I'm not sure about the scale of the hardness numbers. As there is a test for wood, and a test for soft metals, but there isn't an exact unit (that I have seen) for testing wood with a clear coat on it. The unit I used was setup for somewhere between wood and bronze, which I figured was sensitive enough to see if there is a difference. Using your formula roughly, extended out to best and worst case scenarios, there could be well over 1mm of difference, and that's assuming the scale of my readings were correct. Also, it was only a dozen pins, so the sample size wasn't really that great.
Honestly, I'm in the camp of it's not that big a deal really, but where it is a problem is the fact the playfield with the lowest hardness numbers had ghosting. Not saying it is definitive, but it definitely seems correlated. I also believe that when people say they see "cratering" vs dimpling, there is actually a difference, as I have noticed it myself. A decade ago, I never even noticed my playfield, as it looks the same as it did 10 years ago, 5 years ago and this year. I did notice it when I had two nib pins right next to each other, and one looked like hammered dogshit, and the other looked hardly noticeable unless it was under the perfect lighting. Again, to me it wasn't a big deal, but it was different enough for me notice, and I usually couldn't give a shit.
I honestly think the truth is in the middle somewhere. I think there is a difference in playfields, hence the number of people bringing up the issue and my results. On the other hand, I don't think it's a major issue, unless there is a correlation between the ghosting and the hardness, but i don't know definitively.
The reality is, if I was able to get results that different, with a quick little test with no real background on the subject, then stern should too (hell, all the manufacturers). They have a QC dept, if they would invest $5k in a tester or have someone setup a process for them, the majority of the Issues would go away. I mean, how much does a playfield replacement cost them? I have to imagine it's not cheap, especially with the amount of swaps. If they had someone checking the playfields prior to installation, with the proper inspection, then bam, the majority of the issue disappears. Not saying it's a perfect solution, but doing something is better than nothing, as from these forums alone it's clear consumer confidence in them has dropped drastically. I hope for all our sakes they get whatever the issue is figured out, because they make great pins, and it would be nice to know your NIB pin isn't a ticking time bomb.