[Eric Roach]

George: I just took a look at a 3.5 oz Gibbs Polaris.; you’re weren’t kidding, that is a very shallow cup. The head is about 1.25” thick here. I’m sure there is some variation, but on mine there is a perfectly circular, 1.125” cup sanded into the slanted face. It’s approximately .140” deep. Approximately a 4.5” sphere would be needed to create that arc, so that was a good estimation.

Using the Polaris as a guide, a 1.125” circumference popper (like the W-Y) would call for a cup 1” wide, which would leave a 1/16” rim around the middle of the slanted face. Proportionally, the cup depth should be about .126” which calls for a sphere approximately 2.5”.

Frech mentions in the article the importance of making his poppers exactly the same, but I imagine he had some variation because he tooled the cup by hand. It would be great to see an original W-Y to get a better idea of the cup, but I guess it's time to start experimenting with the cupped face to see if it's possible to get a copy to mimic the differing actions (including swimming) he mentions in the article.