Breaking in EP Stones

changeofseasons

changeofseasons

Joined
Jul 15, 2009
Messages
156
So I added a 1200 grit Boride Edge Pro stone to my collection of already broken in Edge Pro stones. I wanted to experiment and try out that new stone on a knife to see what kind of noticeable difference there was in the polish of the 1200 and the lower grits. There was a difference in the edge polish. The 1200 left a much worse (cloudy) polish than the nice clean polish the 1000 grit left.

This got me thinking about a number of things. First, why have I not noticed this before? I've never seen a post about breaking in EP stones. My new stones were cleaned, so I don't think there was loose dust or abrasive causing the issue. I guess I never noticed this issue before because I've never mixed new and old stones. I do limited work with the edge pro and I don't do any reprofiling with it. Even though I have two sets of stones, I'm still on my first set and they seem to last forever. It's hard to remember back to when the stones were new, but I think that the finer stones all left a cloudy scratch pattern back then. I just didn't think about it because my edges were still shaving sharp and I would then clean up the edge with tapes or a strop.

The one thing the older stones had done to them was that they had been flattened a few times. I use wet/dry PSA SiC paper stuck to plate glass. Sometimes I'll use a course diamond plate. Either way, I finish by rubbing the stones against each other to smooth them out a bit.

Has anyone else experienced this before?

My best and only theory as to why the older stones polish better is that I am "glazing" the stones by rubbing them together after flattening. I'm thinking that just as you can use the smooth side of a SiC dressing stone to "glaze" a 220 grit Tormek style wet grinding wheel to cut more like a "1000 grit" stone, I'm doing the same thing to my old EP stones after flattening them. If my theory holds true, this would help to explain why even my old 220 removes very little metal and begins to leave a bit of shine on the edge.

Sorry for the long post, but I've got a new puzzle to solve and I'm a bit obsessive about puzzles.

Any thoughts or similar experiences?
 
I've had the same result... the 1200, even after lapping, doesn't seem to leave as fine a finish as the 1000. I think it's just the stone.

And you're right about "glazing" the coarse stones. They work much better being flattend with SiC powder than they do with other methods. Huge difference.

cbw
 
Perhaps the 1200 stone is simply the culprit. I'm going to regrade that stone a little bit tomorrow and see if I can get better results with it... just to be sure.
 
not familiar with the way the actual edgepro 1200 works but often the stones in and around 1k while not being 1k like 800 king and 1200 king leave hazy finishes they are not by anymeans finishing stones they are lead in stones to polishing to much higher grits

not every stone leaves a shiny bevel and several stones around that grit range are used to fake the hazey finish on hon kasumi knives by using them to establish the haze with very specific followup methods.
 
So I got the EP out again, flattened the new 1200 stone a bit, and gave it another go. I was more careful to check the edge after each stone this time. Basically, the old stones from a few years ago just leave a better polish for some reason. My 220 through 800 stones are old. The 1000 and 1200 are fairly new. The 800 stone is the most different (being yellow) and it left the most polish of all the stones, a near mirror polish. The 1000 and 1200 are finer grained, but they did cut faster and make more swarf. Also, the polish they left was hazy, not as bright as the 800. I checked the Boride Abrasives website and couldn't find any yellow stones. So I guess they're discontinued. I'll check in with Ben Dale soon and see exactly which stones have which model number so I can figure out the difference in how they cut.
 
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