If grooves don't have any impact on spin then what was the big battle between Ping and the USGA about? I doubt that the type of grooves on a clubface would have any other impact that would upset the USGA. If I'm not mistaken, even though Karsten won the lawsuit, he did agree to space the grooves a little farther apart. If there was another reason for this I would love to hear it. Anyway, even though I suppose it's not a "science paper" here is a link concerning the grooves on a clubface. It mentions Ping and also what the USGA and PGA would like to do now.