Mike

Sounds like you have a baseline and are at least happy with edges you have produced. Moving to natural finishers is more difficult, than say a 12K SuperStone edge and can cause you to chase the elusive finest edge, like so many of us.

First let me qualify that “Hair Test are over rated and not a definitive test.” Why? Because all of us have different hair. What I do is at 1K, once I feel the bevel is sharp, based on how it feels on the stone, how the edge feel on the thumb pad and looking at the edge under magnification.

Take the spine rest it on your arm, rotate the edge about 3/8 to ½ inches off the skin and move the blade against your arm hair at the top of the hair. I am looking for the edge to grab a hair. Do this at 4 different points on the edge, beginning near the tip, then move in ¾ of an inch, ¾ inch more then near the heel. You should be grabbing hair or cutting them all across the edge.

The bevel is set, both sides of the bevel meet at an even point across the entire edge, it is sharp, now begins the polishing. I do some extra weight of blade laps, 10-15. At this stage edge is sharp and I am beginning the polishing process.

When you honed the bevel the grit on the stone created a series of mountains and valleys, lands and grooves. If you were to shave with this edge the land peaks would dig into you skin, you would cut hair, but also cut skin. Perhaps not enough to draw blood but it will be uncomfortable.

The goal of polishing is to reduce the height of the land, tops while maintaining and enhancing the edge keenness. So we use a progression of stones and possibly paste to polish the height of the lands as close to the groove. With synthetics this is not too difficult, if you introduce a Natural stone you do not know exactly where the Natural stone fits into the progression. Natural stones cannot be rated because they are made naturally, not under controlled condition. While most of the grit may be X grit there may be other grits included. Remember rocks are created by wind, water and time,(thousands of years). Just one single courser grit can affect the honing results.

So introducing a Natural may subvert you synthetic progression. Only by experimenting will you know where your particular Natural will fit in your progression. It may very well be less that your 8K. Add to that the different quality or type of stones. Coticules are frangible stone that the grit of slurry breaks down to a finer grit, creating more polish. Other stones like the C12K do not or not to the extent of a Coticule.

Lapping a hard stone like a C12K is labor intensive because of the hardness it is also the quality that may make a good finisher. First draw a pencil grid and lap on a piece of wet and dry or a stone to check for flatness. The goal is to smooth the stone face, it does not have to be perfectly flat. Smooth is more important than flat. I just want it relatively flat, lose Silicone Carbide grit and or Wet & Dry sand paper with water will get you there, it is messy. I go to 320 then lap with a Hard Arkansas stone with lots of water and Diamond or CBN paste if you have it or use you synthetic progression ending with your highest grit stone with lots of water.

Get the stone as smooth as possible, then burnish the stone face with steel. I like honing 2-3 kitchen knives with pressure. It won’t hurt your knives and will leave a smooth face on your stone.

Try your stone with Smith’s synthetic honing oil (Lowes or Ace Hardware) with water and many laps after your 8K, as many as 100 or more laps. If it is a hard stone 1-200 laps is not unreasonable. You may also experiment with pressure, I find honing with pressure works well with Arkansas Blacks and Translucent for some razors, they are similar in hardness to C12k’s.

By the way Smith’s works well with Coticules, try light pressure and more laps.