Polish Zloty KM49.1 thick & thin?

Every collector of world coins will have some amount of Polish Zloty's, KM#49.1. It's hard to avoid them. Here's my little pile:
    The extremes side by side:
From left to right: 1975mw-1975kr-1975mw-1977mw-1985mw-1976kr-1974mw-1974mw

I noticed a considerable variation in thickness: both 1974 coins are thinner than average, while the 1975 coin on the left is thicker. For convenience, I add a scan of the extremes right next to each other.

Is this variation systematic? Is it documented?
For certain coins from elsewhere, variation in thickness is rewarded with a KM-subnumber!

Since I'm a type collector, I was looking for one coin with mw-mintmark and one without, but I did add the 1974 coin as a 'thin planchet' variety to my collection.

​Hi,

in my collection the thicknesses vary from 24.99mm (1975 no mint mark) to 25.12 (1981 with mint mark). Those are normal deviations, so I've not thought about "thin or thick" planchets. On the other hand I noticed that your coin (thin planchet) has rounded "shoulders", which makes a coin looks thinner than it is. Did you measure the coins or is it only a subjective feeling?

Ole

It sounds like you are getting "thickness" and "diameter" mixed up.

Quote: "Cerulean"​It sounds like you are getting "thickness" and "diameter" mixed up.

​Hi,

Indeed, I did, here are the corrections:

in my collection the thicknesses vary from 1.87mm (1968 with mint mark) to 2.06 (1985 with mint mark). Those are normal deviations, so I've not thought about "thin or thick" planchets. On the other hand I noticed that your coin (thin planchet) has rounded "shoulders", which makes a coin looks thinner than it is. Did you measure the coins or is it only a subjective feeling?

My 1974 with mint mark is 2.04, the 1975 without is 2.05 and the 1975 with is 1.94! Also inside the normal deviations.

Ole

I'll come back to this thread once I can lay my hands on a caliper.

Quote: "ArnoV"​I'll come back to this thread once I can lay my hands on a caliper.

​Hi,

try amazon, here is the link from amazon.fr
https://www.amazon.fr/LOUISWARE-Professionnel-inoxydable-Microm%C3%A8tre-daffichage/dp/B01MAY5ECH/ref=sr_1_1?ie=UTF8&qid=1540840865&sr=8-1&keywords=caliper

Ole