(originally posted in Hones by mistake)

I am wondering if anyone on the forum has ever experienced something similar with their hones.

I have a 250/1000, 1000/4000, 6000 and 10000, all King/Ice Bear waterstones. I know the progression looks a little funny, they were bought piecemeal for other purposes. I also have a slurry stone which came with the 10000, and I understand it to be 12000 grit.

I'm not an experienced honer, but have been able to get very passable edges with these stones, a pasted strop, and a plain leather strop.

However, I have started noticing something which I can't quite explain. I can get a very smooth polished edge off the 4k, first using a slurry, then using the stone clean. I can pop hairs no problem off the 4k. I started to notice that using a loupe, I couldn't really see any significant improvement in the edge after the 6k and 10k, and in fact, I never quite get back the smooth polished edge I get off the 4k after going to the 6k and 10k.

So, as an experiment, I stropped a razor after the 4k, tested it, and then went back and took it through the 6k and 10k, stropped and tested it again. No appreciable difference. As a further experiment, I took a scrap razor which was warped and has a very wide bevel on one side. I honed it without tape on the 10k, then put two layers of tape on the spine, and created a secondary bevel on the 4k with slurry, then polished the edge on the clean 4k. The idea was to get two bevels side-by-side, from the different stones, to compare them definitively. After seeing the two side-by-side, the 4k certainly does polish better than the 10k.

The question is how to explain this.

Hypothesis 1: Are the grit gradings on the stones inaccurate? They stones are all the same brand, so I don't think this is likely.

Hypothesis 2: Have the higher grits somehow become contaminated? I lap the stones using emery paper on a flat surface, and then minor lapping/cleaning with the 1k.

Hypothesis 3: Are there other variables which matter as much as grit size? I like using the 4k stone, it cuts fairly fast with a slurry, and I find the way to get the polished edge is to hone lightly on the clean damp stone, and let the stone get a little clogged with swarf. Is this clogging partially obscuring the cutting particles, allowing the stone to behave like a much finer stone? The 6k cuts slowly, the 10k more quickly, but neither clog in quite the same way as the 4k.

Hypothesis 4: Is it something to do with the slurry stone? If it was in fact a higher grit than 12000, this might explain why the higher grit stones done't seem to contribute much.

Any thoughts?