I recently started making wooden hand planes and the steel I have been using was reclaimed sawmill chipper blades (extremely hard) and some O1 oil hardening tool steel that I purchased. After trying multiple methods for ensuring I had a dead flat surface I expended a lot of energy and pretty much wore out my Norton 1000/4000 water stone. After researching diamond whetstones quite extensively it appeared as though the DMT stones were the best way to go. I purchased the Dia-sharp fine, extra fine and extra/extra fine stones for my needs thinking I could do the coarse work using emery cloth on my lapping plate and my water stone for the coarse grind on my primary bevel. I found the fine to cut quite agressively (compared to water stones) but this was somewhat expected. 20 strokes on the fine stone had a consistent scratch pattern across the back of the blade. Another 20 strokes on the extra fine created a lighter scratch pattern and another 20 strokes on the extra/extra fine left a very fine scratch pattern. I anticipated a little more polish with the extra/extra fine as it is listed as a 6000 grit. My 4000 grit waterstone will leave a more polished surface. However, the blade was sharp but not quite what I anticipated. A few passes on a strop though had the blade making fine strips from the edge of paper. In total I spent about 20 minutes in this process where a waterstone would have been over an hour and require me to flatten the stones a couple times. In the attached photo the blade sitting between the two plates had a bad trip on a power lapping plate which caused it to be ground more on one side. It only took 10 to 20 strokes on each stone to get a consistent scratch pattern at the business end.