If you're interested in an excellent superficial hardness tester I can recommend this: Portable Ames Model 2S Precision Hardness Tester Rockwell w/ Accessories | eBay
$800 is a good deal relative to the regular price. Just the ticket for quantitative analysis of your hammer tensioning results. Maybe you could make an offer?:dev:
Very tempting but if I was going to spend that kind of money in pursuit of my obsession, I think I might go with a re-toother first.