A few years back I purchased a top grade true black 4" X 7" primitive from Dan's it was anything but flat, took hours of lapping by hand to get it flat. I have experimented with the surface prep on that stone a lot, had it to near mirror at one time. It would put a very good edge on a razor but took a LONG time to get there w/that shinny surface. I now keep it with an 800-grit surface burnished a fair bit, finishes edges beautifully and doesn't take a lifetime to get there.
I also have an old vintage Pike Norton Surg.Black 2"X 8" as a two-sided system, one side I keep freshened @ 600-grit > lightly burnished the other is about 1K > well burnished. I use it mostly as a way to refresh edges when traveling or I'm away from my other stones. Just touched up a little 5/8th's Geneva tonight on this old Norton and the HHT was just excellent, I'm certain the shave in the morning will be outstanding.
As I stated earlier, I normally use Balistol & water about 50-50 mix then dilute to almost plain water as I finish. I do use other lubricants at times depending on how the edge feels on the stone or just the mood I'm in.
I also have an old vintage Pike Norton Surg.Black 2"X 8" as a two-sided system, one side I keep freshened @ 600-grit > lightly burnished the other is about 1K > well burnished. I use it mostly as a way to refresh edges when traveling or I'm away from my other stones. Just touched up a little 5/8th's Geneva tonight on this old Norton and the HHT was just excellent, I'm certain the shave in the morning will be outstanding.
As I stated earlier, I normally use Balistol & water about 50-50 mix then dilute to almost plain water as I finish. I do use other lubricants at times depending on how the edge feels on the stone or just the mood I'm in.