a picture
may be worth a thousand words, but not that one
how did your lapping lessons come out ?
a picture of the fringes will suffice
but wait, let me guess
-> it had a pretty fair hump in the center (or thereabouts)
I know this because
I too am expert at making humps - as is everyone else doing it by hand
sooo, I have started to build a DIY lapping machine
off eBay
it has a 5" diamond lap, but no problemo -> 8" here we come
note that while this approach may work out ok for me in a lab setting,
for production it would be about worthless
Swiftech has a custom manufactured
42 inch diameter Lapmaster
(Neo - you really should stop your twaddle about "first rate" this or that, you do not have a clue about what is being done by the 'big boys')