Originally Posted by
Ecl
Money spent on the Norton flattening stone is wasted for our uses. Maybe the axe and chisel folk can find a use for it, but otherwise it's a doorstop.
The coarse DMT (325 grit) is the way to go for normal lapping purposes. The extra-coarse can be useful for dealing with seriously out-of-true stones, but if you only buy one lapping tool the coarse will serve you well. If the cost of the 8 inch plate is a problem, the cheaper 6 incher will also do, though it requires a little more finesse to ensure that you don't dish the stone.
Before touching a stone, DMT plates should be prepared with some figure-eights on a rough surface, such as a sidewalk or out-of-the-way garage floor. This will knock off any outsized diamonds that would otherwise gouge furrows in your hone. Only takes a second.