sharpining / blade geometry questions

[poleclimber]

Ok guy this is my first post, I've carried and used knives for as long as I can remember, and have always had a fascination with them, only recently have I really had the hade the money for anything beyond what you could pick up from the local wall-mart. The knives I currently own that I would consider higher end are a BM810 a spiderco Ti Military, and Zt 0180. I love these knives and carry one of the every day to work. My question is maybe more to do with the steel than the sharpening. I would say I can sharpen a knife pretty well and for all of the above I freehand on a diamond stone and finish on a sharpmaker, and im very satisfied with the results I get. What im curious about is the fact that I cant quite get my cheaper knives Case sod-buster for example to be as sharp as either the BM or spyderco. and from what I know about blade shape and geometry I would expect it to be capable of slicing much better than the others as it is much thinner and has what I would call a full hallow grind (maybe the wrong terminology) however that is no the case. So my question being is this due to lower quality steel or just not enough experience sharpening . Again Im not used to the more expensive knives but would in no way consider myself lacking in basic sharping skills as I can get all of the above knives to cut much better than they did w a factory edge. Thanks in advance for any responses and suggestions.

 

[FortyTwoBlades]

It's possible to get an insane edge on just about any steel if you work at it hard enough. Chances are you're just running into one of any number of common sharpening pitfalls. It's possible you either haven't fully apexed your edge or you're fighting a burr.

 

[poleclimber]

thanks for the response ill keep playing around with this case and if I can get it any better

 

[rycen]

Moved to MT&E

 

[Primitivepete]

Your bevel may not be ground at the same angle on each knife. My spyderco came with a bevel close to optimum. My case knives came with a higher angle than I like so I changed it with a file before sharpening. easy fix

 

[Obsessed with Edges]

You might need to adjust to the lower wear-resistance of the Case blades, if your touch is accustomed to sharpening higher-wear steels, like S30V. Case's 'Tru-Sharp' stainless (420HC) will burr easily, especially on ceramics (ala Sharpmaker, etc). And if using a diamond hone for setting bevels, it's best to keep the grit at a finer level (Fine/EF) for that; coarser diamond will be overkill on these steels, leaving edges very ragged with heavy burrs. Case's CV won't burr as much as the stainless, and only needs a very gentle touch; it's very easy to grind & set bevels on, with virtually any hone or abrasive. Either steel will respond very well to SiC stones or wet/dry sandpaper, in particular; and for stropping, any of white rouge (AlOx), Mother's Mag paste, Flitz or Simichrome pastes, and green compounds work very well on these steels. For what it's worth, a lot of my daily-carry knives are Case, in both stainless and CV. They respond very well to the methods I've mentioned, and are very capable of scalpel-like sharpness at thin edge geometry (Case's hollow grinds are ideal for this).

It's always possible the edge geometry can be an issue on any factory edge. When in doubt, I ALWAYS go a bit thinner at the edge, down to ~30° inclusive or sometimes lower; that ALWAYS improves cutting, so long as the edge is fully apexed and burr-free.


David

 

[poleclimber]

ok guys thanks for the advice I think ill shoot for a thinner edge and see what sort of results I can get. I would say that many people would be happy with how it is currently so I have to admit this is really something ill be doing more for fun just to see exactly how sharp I can get this thing more than any practical purpose. Already the knife cleanly push cuts printer paper, slices phone book paper and paper towels. And will start to cut TP. So what is beyond that do you folks have any test you like to use for sharpness and am I pretty well at the limits with to tools I have available or with the right angle and right amount of stropping can this thing be made to do more.

 

[RX-79G]

Another possible source of frustration is the tendency of some of the smaller knife blades to flex under sharpening pressure. This can make the actual sharpening angle variable.

 

[Bludgeon]

ok guys thanks for the advice I think ill shoot for a thinner edge and see what sort of results I can get. I would say that many people would be happy with how it is currently so I have to admit this is really something ill be doing more for fun just to see exactly how sharp I can get this thing more than any practical purpose. Already the knife cleanly push cuts printer paper, slices phone book paper and paper towels. And will start to cut TP. So what is beyond that do you folks have any test you like to use for sharpness and am I pretty well at the limits with to tools I have available or with the right angle and right amount of stropping can this thing be made to do more.

Next step...whittling a strand of hair.