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We have a massive amount of Edge Pro products so we figured it would be good to have a whole section on how to use the machine and what to use on it.
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Thinning a Richmond Artifex M390

Tue Jun 10, 2014 10:21 pm

so I typically run a 14.45 degree angle with a 1k 3k 5k chosera progression. I want to really improve the knife's performance for detail work. can anyone recommend an angle to thin at from their own experience? I have sharpened many knives but never thinned one. Thanks a bunch in advance guys. your knowledge is always appreciated.

Re: Thinning a Richmond Artifex M390

Wed Jun 11, 2014 6:18 pm

ml, if you're using an EP Apex, I'd run it at as low an angle as possible while still hitting the edge bevel shoulders (where the "V" meets the blade face). Grind at that low angle getting as close as you dare on each side to the actual edge. DON'T grind all the way to the edge of the edge or you risk putting overgrinds (valleys) in the edge profile (shape). Sharpie is your true friend here, as is magnification :-). Run through your progression on this relief bevel till it's shiny, then go back to your normal 14.5* angle and put a small, consistent edge bevel back on the knife, running through your progression, deburring, etc. This part shouldn't take long at all. Now the thinning is another matter - you'll be removing a lot more metal that cutting an edge bevel and on pretty wear resistant steel at that. If you have a coarse stone or diamond plate for the EP, this will be much easier than starting w/a 1K stone.

I've run real low angles on the EP Apex by using the plastic base at the bottom of the vertical rod as my "stop collar", putting the stone right on that for spacing adjustments on the sharpening rod clamp.

Re: Thinning a Richmond Artifex M390

Wed Jun 11, 2014 10:17 pm

Interesting question. Can anyone tell me how low the Edge Pro can go in terms of sharpening angles without resorting to "tricks"? And is this sufficient for thinning knives?

Re: Thinning a Richmond Artifex M390

Thu Jun 12, 2014 3:15 am

Mark, I haven't measured the angle, but I was able to thin an Artifex 52100 Gyuto very nicely at the bevel shoulders with an Apex and Shapton GS stones.

Re: Thinning a Richmond Artifex M390

Thu Jun 12, 2014 6:27 am

Steve, thanks. How much of the blade did you sharpen then? Was it just the bevel shoulders or did you also remove metal from part of the blade, e.g. 1 cm?

Re: Thinning a Richmond Artifex M390

Thu Jun 12, 2014 7:02 am

I have quite a busy restaurant week ahead of me so I will not be able to sharpen again till Monday. That being said, I am extremely grateful for all of your feedback. Unfortunately, some of the terminology leaves me slightly lost. Edge bevel shoulders (where the V meets the blade face) is there a photo or video of this? how does magnification come into play? I am fortunate to have a diamond plate so that should help. Thanks again for your patience and feedback.

Re: Thinning a Richmond Artifex M390

Thu Jun 12, 2014 4:08 pm

ml, look through this thread: how-to-set-a-primary-and-secondary-bevel-using-ep-t6709.html. On the diagram, what's labeled the primary bevel, the shoulder is where the angle of the primary bevel meets the main part of the knife or secondary bevel as labeled on that diagram. We're talking about easing that angle into the main part of the blade, by creating another bevel above the primary edge bevel that's at a much lower angle (more acute).

@ Mark - I'll set about taking a photo or two of the Artifex 52100 Gyuto to show where and how much metal I removed for the thinning.

Re: Thinning a Richmond Artifex M390

Thu Jun 19, 2014 6:02 am

I cannot speak to THIS particular knife or Bohler M390 on kitchen knives, but I have numerous fixed blades and folders in M390 MicroClean and it is one of my favorite steels. On most of my M390 folders, I have the edge set between 10-12.5 degrees using my EP...and what blows me away is that still the edge is phenomenal at resisting deformation despite the thin angle! Most of those angles are just reprofiles rather than full thinning (other than how the secondary bevel increases in height with the new angle being applied, of course). Sometimes I feel my EP gets depressed given the frequency of touchup of my M390 blades is perhaps 1/10th of it for something like 440C.

I have thinned a fixed blade in M390 once...and I hope never to do it again. The steel is so darned wear resistant that even the EP 120 struggles, takes forever, and leaves sludge that looks like a sewer line burst all over the knife.
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