Will, take a look at
http://www.practicalmachinist.com/vb...tester-193040/
I asked about how to use them after buying one and got some helpful information.
The link to the rockwell.pdf file in that thread is bad but I've got a copy of it on my website:
http://www.eurospares.com/graphics/m...ardnesstester/
That should at least get you a start.
cheers,
Michael