Rod: Doooh, having seen the same picture on another forum I've now realised who you are! Ah well, us country boys are a bit slow,
and we're almost in the Fens here.
The hardness tester looks really neat, and made me dig out and read the original articles last night. It is also interesting that you are getting good results; that's encouraging. I have a full size tester that works on the same principle, as a result of a 'bother I won it' episode on Ebay. However, I have no manual with it, and while I understand the principle of operation I've never got to grips with it. Your posting has given me a bit of a kick to get on with it. Currently I use a set of specially hardened files to test hardness. They work, but go up in steps of 5 Rc, so are not particularly accurate. They are enough to tell me that I've failed to harden something properly though.
Andrew