Ontario Rat-7/ Sharpmaker function

T

travistheone

Joined
Aug 16, 2006
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116
I have a Rat-7 that i sharpen on my Sharpmaker, and I have been realizing it is not sharp at all. Is this because of the angles, I put the SM on 30 degree back bevel for 40-60 strokes to try and get that edge out of the way. I am puzzled, any hints?

Thanks
Travis
 
I suspect the factory edge is more obtuse than the 30 degrees you're trying to sharpen it at, so you aren't actually touching the edge. Use a black marker to colour the edge, and then try sharpening it again. You'll be able to see exactly where the steel is being removed.
 
moving-van.jpg
 
My RAT-3, if it's ground anything like the RAT-7, is ground at 40 degrees... or thereabouts. Even at the 40 deg setting, I have a very hard time getting the entire length of the blade sharp. If you're sharpening at 30, you might just be sharpening the shoulders and not really touching the edge.
 
And 40-60 strokes are nowhere near enough to reprofile the edge from 20 down to 15. Try something in the range of 1000 strokes on the grays with frequent cleaning of the rods. Well, since the steel is 1095 you might get away with a few hundred strokes.
 
get some coarse wet/dry sandpaper, clamp em to the rods with those black paperclips, and watch the metal fly. (well, not really, but watch the process go alot faster)
 
Hmm, I like the last tip. I am backpacking this weekend, and will just use the Rat as is, and bring another knife for the tasks that require razor sharpness.
Thanks for all of your help.
Travis
 
I've been trying to rebevel my new RAT-7 as described as above. I'm using the magic marker method to confirm that I'm not sharpening the edge but rather removing the shoulder of the current bevel.

I'm doing okay an the straight portion of the blade but I think I might not be doing it right around the curve and at the tip.

I am using a Sharpmaker with 320 grit wet/dry paper clipped to the grey rods and am using the 30 degree back bevel holes.

Any help would be appreciated.

-- FLIX
 
I do it this way (experts chime in)
As you stroke, from the top down, you are at the same time pulling the knife toward you. This I assume you are doing. When you reach the "belly" of the blade as it begins its upward sweep toward the tip, your wrist should be turning down. Does that make sense? I don;t really know how to put that into words. Your stroke down and back continues and your wrist curls down starting at the beginning of the curve of the blade.

Hmmmm. I'm now confused. :D
 
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