Quote Originally Posted by Bart View Post
Let's look at it theoretically. Spessartine Garnet (the cutting medium in Coticules) has a hardness of 7.5 on the Mohs scale. Razor's steel hardness typically varies between 56 and 64 on the Rockwell-C scale (HRC), which is a very wide spread. If we convert HRC into Mohs, we get 5 Mohs for HRC 56, and 6 Mohs for HRC-64. Conversions were done here: eFunda: Convert Hardness: Rockwell C-Scale
Both Mohs and Rockwell-C are non-linear scales. The differences in hardness between 56 and 64 are immense.
Bottom line, the answer is yes, you can expect differences in performance between various steels on a Coticule. The diamonds of a DMT-plate are 10 on the Mohs scale, but those slowly become rounder over time, which affects the performance, while the Coticule works with a constant flow of fresh garnets. In practice I've not found any problems doing bevel work on either a Coticule or a DMT-E. I can say that my DMT-E is tamed enough to no longer offer better speed than a typical Coticule, and it surely is surpassed by my faster ones. When I feel the need to drop down, I usually drop down to the DMT-F. It doesn't take much time to deal with the 600 grit scratches of that hone, on a Coticule with slurry.


By all means, I'm not here to talk you into using the Coticule at all times. Whatever sets the bevel is fine of course. But you could have literally been 20 laps from home, when you decided to go to the DMT, so it's impossible to draw much conclusions here. There's one important detail to mention: the complete bevel off the DMT will shave arm hair far more easily than that off the Coticule with slurry. Off the DMT, it often even passes a HHT. I have noticed that off the Coticule with slurry, some razors really can only barely manage to shave arm hair, certainly if the slurry was on the denser side in combination with the light-pressured back&forth strokes. When I feel it's time for testing, I often optimize my slurry (meaning that I add a few drops of water if it looks rather dense) and perform about 10-20 regular X-strokes. Expecially when you notice that the razor was starting to show "arm hair" responsiveness, but it didn't improve after another round of 20-30 laps, you must suspect that the edge just maxed out on slurry.
Be my guest finding it all a bit easier on the DMT-E, I'm just trying to stay close to the original premise of this thread.


So far, I personally have not found much truth in that statement. I've honed from rather soft vintage Sheffield wedges to the extremely hard TI Silverwing, over stainless steel cryohardened Friodurs and Dovos to Manganese steel Bartmanns. I have DMT's at my disposal, a selection of Belgian naturals, the Choseras 5K and 10K, and a Nakayama. I never really found any steel related rules applicable to the choice of hones and honing methods. My face can discern between the hones, but my razors can't. At least not that I'm aware of.

Best regards,
Bart.
Bart, I'm not trying to suggest that the DMT 1200 is better than the coticule or anything like that, I'm just pointing out some findings I've had with this method so that others might know what to expect. I hope you don't think I'm trying to drive us off topic that the DMT 1200 is a better bevel setter or anything like that, or that it fits into this method or whatever, I was just using it as a point of reference of how long I worked the coticule and how long I worked the DMT, and what the results were.

I very well may have been 30 laps from home so to speak, but I really don't think so. I was seeing virtually no improvement of the edge in 30 stroke sessions. I was doing x strokes the entire time (no back and forth strokes). I didn't purposely water down the slurry at all, but I do end up adding some more water over time which does water it down a bit, and eventually I would refresh it. I don't use the slurry circling technique yet and after 50 or 60 strokes, I feel the need to refresh the slurry because some of it has fallen off the sides causing the stone to dry out a bit. I actually lose quite a bit of slurry when I rinse the blade too as the blade seems to hold a bit of slurry in the hollow grind. Anyway, from completely dulled, I DID detect some improvement, but it seemed no matter how many strokes I would do, I couldn't get it shaving arm hair or passing the TNT to my liking.

Within 20 light strokes or so on the dmt, though, it was passing all my usual tests at that stage with flying colors (effortlessly popping arm hairs at skin level, and great TPT/TNT results). I too have found that edges off of the dmt are ridiculously sharp in a "will pop arm hairs with ease and slice right into your thumb pad" kind of way, but I did have very nice results off the coticule too with the other razors it worked for, and those razors worked out really well in the end.

Maybe I did just max out the sharpness off the coticule with the slurry level I was at, and needed to water it down some. That would definitely explain my results. I'll have to keep this in mind in the future and try at it again. Or maybe I really was just a set or two of 30x away from being there.

Either way, the shave was fantastic this morning

Thanks for the further info and details. If you can get this method to work on all of those types of steel, then it's clearly me and not the coticule. I'll keep working at it and practicing