"Grading scale" of wobble and what's acceptable.

Hey guys, it's great running across this forum. I'm new to cast iron and trying to gain as much knowledge as possible to educate myself. I've read through the forums and know it has somewhat been addressed, but is there a way to determine the severity of "wobble". I know you can listen for the "click" by tapping the rim or attempting to spin the skillet. Both of those seem fairly subjective though. Should the skillet not spin at all unless you forcefully attempt to spin it? Is there a way to determine what is acceptable by doing something like seeing how far a credit card will slide under the edges all the way around? I ask because I just bought my first #8 Griswold, which the seller adamantly says is flat, but when tested on several surfaces after receiving it, has a slight wobble and will spin when I push the handle. I'm wondering if I'm being too critical and should not expect a perfectly flat piece or if my thinking is correct this is not acceptable. Thanks in advance for the help!

This video of Dougs helped me. Maybe it will help you also.
http://www.castironcollector.com/damage.php

Thank you for your reply Bonnie! I did watch that video but I'm hoping to go a little further than just establishing there is a wobble.

Acceptable depends on the purpose and the individual buyer. If I'm buying a pan as a user and I'm cooking only on a gas burner grate or oven, a little wobble doesn't matter. A lot of warp/wobble still does, though.

Some pans, more than a few, came from the foundry with a little hump or bump that, depending on location, make for a spinner or at least a swiveler. They look flat, and might even pass a quick straightedge test, but they're not perfect. On those, it depends on how picky you are as a collector or how badly you want one of whatever it is.

I don't think there can really be a scale, as there are other subjective factors that play into each piece.

Just a little advice based on experience, I purchased a #12 wagner skillet from ebay and the seller was also firm in their opinion that the skillet was flat. Upon receiving the skillet it was immediately obvious that it had a quaters thickness warp. I contacted the seller and told her it was warped, she said it wasn't, I offered to send her a video of it on several surfaces. She responded saying she would refund half the purchase price to avoid a negative review and additional shipping cost. I mostly wanted the skillet for pancakes and on my electric stovetop the wobble made no difference at all. So in short, if like Doug mentioned if it will be a user and you want to keep it you may still work out a discount with the seller.

When buying online, I always ask "on a hard, known level/flat surface, does it set flat with no rocking or movement when pressing down on the rim at various points? Does it spin or swivel on that same surface when the handle is batted sideways?" That is about as specific as you can ask. How satisfactory the answers are is up to the prospective buyer.

Thanks for all the advice guys. All the skillets I buy will be users but my goal is to buy only one great condition piece in each size and pass down one day. I ran a quarter around the edge of the skillet and without depressing any side of the rim it never went under except for about 1/4 of the way from the 9 o'clock to 10 o'clock position. When depressing the opposite rim it would go under about half the quarter in the same position as before. Is that fairly acceptable? Doug, would you mind posting a video giving an example of what a "flat/no wobble" piece would be like under the same wobble and spin test you did on the damaged piece?

Some sellers will go so far as to describe that a small wobble will be negated by the thickness of a credit card, a couple of sheets of paper, or similar, in order to give an idea what degree the piece is warped. There's not much a video of a flat pan would show other than it doesn't spin, rock, or click. Plus, there's also the opposite scenario to consider-- that the bottom is not flat but bowed upward. The same tests for a downward warp would not reveal that.

Gotcha. Thanks Doug! So with a flat bottom there should be no click whatsoever and no spin at all (well of course unless you slap it with some stank behind it haha)?