Q: Is there an in between process for knives that have a decent edge?

Obsessed with Edges said:
Your earlier mention of your 440C blade's troubles made me immediately think of Buck's older 440C blades. An awful lot of their older 110 and 112 folders in 440C eventually ended up with broken tips. Saw a lot of those up for sale on eBay back then, and it always made me wonder what Buck's spec was for hardness in those blades. And back around the same time I was reading here about ZDP-189's toughness limitations at high hardness, I also remember reading about a lot of troubles with D2 blades breaking and also reading about how it was apparently much trickier to heat treat correctly without diminishing the steel's toughness.
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This was one of Wenger and Klötzli of Switzerland, but some “special” steel. Very different from what was used to.
 
I learned that anything less than a fast cutting stone is worth messing with even for a touch up. I've either use a 1k grit fast cutting cermic stone for things like my kitchen knives, or I will use a fast cutting 600 grit dia-sharp diamond stone to touch up my pocket knives and get them wicked sharp without danger of removing too much material on a belt driven system. Sometimes I hit the edge with the 600 grit fine diamond and then smooth the edge out on a smaller extra fine diamond stone thats probably around 1k grit.

Nobody has time to sit there half a day and use slow cutting stones at high grit, if you struggle to get a nasty edge on a blade at all, go with a 600 grit diamond stone and run it free-hand. You'll never look back.

I thought i sucked at sharpening before but then I got the right diamond stone, then I was like "Oh."
 
Obsessed with Edges said:
Honestly, I haven't. But the vast majority of the knives I use don't really push the limits for hardness anyway. Most of what I use are in steels like 420HC (Buck, Case @ HRC 55-59), Victorinox (HRC 56 by their spec) and Opinel (Sandvik 12C27Mod @ high-50s HRC). All of these are tough enough, that they're really not prone to chipping at all, if they're heat-treated and tempered well.

My takeaway, from the ZDP-189 blade, was that I decided I don't need a steel at such hardness anyway. I reground the tip to an acute point again and it looks great (see below). But I'll never trust that one again for anything but very light use. I don't know if there was maybe some defect in heat treat or tempering with that one, or if what I encountered is typical for that steel when it's ground a bit too thin. I don't want to test such limits again, if I can help it.
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Taking the swedge back out to the tip wouldn't hurt but then again, it apparentlty didn't help.
 
garry3 said:
Taking the swedge back out to the tip wouldn't hurt but then again, it apparentlty didn't help.
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On the few knives that I've reground tips in this fashion, I've sometimes hypothetically considered re-swedging the tip. But I'm not yet so confident in my ability to do it precisely so it looks as good as factory. But I can live without the swedge anyway. And on this particular knife, after seeing how vulnerable the tip is, I'm especially reluctant to do any more grinding on it at all.
 
As many have said, there are so many different steels with endless heat treats. Every knife is different and responds differently to sharpening and stropping.
Most knives I strop until the teeth stop biting. I use whatever grit the knife was finished in for any regrinding.
 
Obsessed with Edges said:
On the few knives that I've reground tips in this fashion, I've sometimes hypothetically considered re-swedging the tip. But I'm not yet so confident in my ability to do it precisely so it looks as good as factory. But I can live without the swedge anyway. And on this particular knife, after seeing how vulnerable the tip is, I'm especially reluctant to do any more grinding on it at all.
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By hand is pretty safe but obviously much slower. It will turn the point into a spear point of sorts making it more durable.
 
garry3 said:
By hand is pretty safe but obviously much slower. It will turn the point into a spear point of sorts making it more durable.
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On any other knife, I'd be inclined to agree with that. But as you mentioned earlier, the original swedge on the tip didn't protect it anyway, after I'd thinned the edge grind. At some point, I'll likely experiment with swedging on a different knife. It does interest me, as another skill to hone for myself.
 
I have a leather strop liberally charged with 10 micron diamond paste. This was not one of the high-priced sprays, just humble waxey Kirby 10 mu on smooth side leather. I carpet taped the leather to MDF, then I flattened the leather to 120-220, using a flat block and very light pressure. The Kirby paste is not expensive, and the waxey carrier wears off pretty quickly, leaving an agressive cutting surface. This leather is pretty firm, but I may try to find a more firm substrate for the next one.

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A few strokes on this strop really lights up an edge that is losing its bite. I use it on steak knives that get a little abuse, and it seems to clean up rolls and snaggle-toothed edges without resorting to a stone. To a degree! If you don't let your edge get beneath decent sharpness, this quick-and-dirty strop will keep it off the stones for some time.

The 10 mu paste removes a little metal, as this strop gets black very quickly. I use it on our everyday kitchen knives at 61 HRC and it does the job of warming up a decent edge to get it cutting agressively again.
 
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