I have to give you a ton of props
@Brew for a well reasoned approach for why/how you know to move on to the next stone in progression. Your thought process is something that, if it were followed by others, would most likely lead to success more often than not. I have honed all of my hundred razors successfully at least once and have been able to compare my “work” to that done by others (via shave test and visually) and can confidently say “I can hone a razor well enough to be a very comfortable and lasting shaver”. I also know others have had me hone razors for them and liked the results. ...That’s said, I KNOW my technique is not something that I consider textbook, and it isn’t always pretty (buts improved a whole lot over time). I have always been heavy handed compared to others but I’ve adapted over time and learned which stones I can and can’t use. I have used synthetic or other, known single grit stones with good results but get the best results and most enjoyment from Coticule’s with slurry stones and hard slate finishers like surgical ark or jasper. I get very serviceable and enjoyable results from a coticule, a diamond pasted strop and my old firehouse/leather strop. I have even gotten great praise from my work done on the welsh slate trio. I’ve also enjoyed using vintage barber hones even though they produce different quality edges that the finer slate edges.
As far as was I look forI can’t say I focus on swarf (mostly because I don’t see much) but I do watch the undercut to make sure the edge is undercutting evenly at all stages. I usually do a slurry dilution progression on a single stone rather than changing from stone to stone so my process is mostly to start by counting strokes (usually something like 50 laps) before diluting the slurry by a drop or two but sometime I will get a feel that should stay longer or dilute earlier. A cool feature of coticule slurry is that it thickens when it mixes with swarf so you do get a visual cue based on the slurry but it’s different from stone to stone. If I’m honing with a light slurry or only water I definitely watch the water wave and undercut but I also feel for how the blade is moving across the stone. i feel for subtle feedback that might be telling me there is a rough spot needing more work, if that spot doesn’t smooth out on water only I go back a step or start over. As I go forward on water only o feel for increased adhesion, the blade starts to get so polished it will feel like it’s sticking to the stone. For this to happen you have to have a lighter touch (my ham fisted approach early on sometimes hides or prevents this sticky polished effect) and your stone needs to be clean so running water might be needed.
I should add a caveat to my “I don’t focus on swarf” statement. I may not focus on the swarf movement, because it’s all muddled up in the slurry, but I do watch to be sure the swarf is cutting and darkening with swarf. If the swarf is not getting dark I will take the razor to a firehouse strop for 50-100 laps, I’ve found stropping on firehouse between stones or intermittently as I hone does a killer job of removing fin edges that kill a honing session. I DEFINITELY strop between stones if I’m using more than one coticule or finishing on a surgical ark or jasper.
I can’t help but think I could/should stay on one each stage longer than I do ...but then I wonder if I’m staying on any single stage longer than I should, undoing the work I have done. My scientific mind says I should stay on each progressively higher grit longer than the one previously...but that same mi d reminds me that the “razor edge” we are talking about gets smaller and smaller as we go and is ultimately measured in microns. Just how long can/should it take to hone that edge to perfection? The visible bevel is just window dressing but it tells us a lot about how that razors edge might look.
