I've seen many requests for a coin's thickness to help in it's ID. I've always ignored the question until it suddenly occurred to me, "How DO you measure a coin's thickness?" The US Gov't DOES have specifications for thickness; I found that. BUT The only procedure I can find to determine a coin's thickness is to stack a bunch of the same denomination, measure the stack height, then divide by the number of coins in the stack. That seems reasonable is you can acquire a bunch of the same coins. But what if you only have one coin? Calipers can give you an accurate measurement but that mostly limits you to the rim measurement. Is that where measurements are to be taken? Doesn't sound too good for worn coins. And what about those 1970-something quarters that were struck on dime stock? BASIC QUESTION: Is there a better, more accurate way to measure a coin's thickness?
I'd use Calipers. Get a good pair with a digital readout, preferrable with a plastic coating on the fingers so you don't damage the coin. I can't think what else you'd measure besides the thickness of the edge.
Just use digital calipers. I got my pair through the ANA many years ago. You really don't need a plastic coating if you just be careful. I used my calipers for many, many years without ever scratching a single coin or medal. Chris
Coins stack don't they ? And they stack because the rim is the thickest part. So yes, that is where you measure. If the rims are worn flat, or even worn significantly, obviously not. And if the rims are worn flat or significantly, the high points will be as well because the rims very purpose is to protect the design. But when a coin has that much wear it is rarely worth worrying about if it is genuine or not. In the cases where it is worth it, then other diagnostics must be used. But in those cases, measurements like weight, diameter, and thickness rarely matter anyway because if the coin is a counterfeit of a valuable coin those things are usually going to be to spec anyway. So the only things that can be used to establish authenticity are those other diagnostics.
And of course the thickness at the rim will also be rather variable because the thickness will depend both on the thickness of the original blank, and on the pressure of the strike. The higher the pressure the better the rim will be struck up and the thicker the rim measurement will be. Yes the government has thickness standards, but they are usually for the strip not the finished coins.
