Geno wrote:I own a Spyderco Tuff and I am a bit worried about how much abrasion resistance the CPM 3V steel possesses and that it will be very hard to sharpen or reprofile.
The diamond /CBN rods are very coarse similar to a ~400-500 grit stone and they will cut any steel at the same speed, it doesn't matter if it is 3V, VG-10, or 1095, all of them (carbides and all) are buttery soft compared to diamond and CBN. This means that the steel doesn't make any difference, you would grind the Tuff with those rods no different if it was 3V or VG-10.
However, how you grind is critical as it has a many-to-one difference on the speed of the grinding and the wear on the stones. Here is how you do it effectively :
-use a lubricant on the rods, water will do, ideally add a small amount of detergent, really ideally use an actual cutting oil
-mark the edge in black
-grind on the 20 dps setting until the marker it almost removed right to the edge
-use only enough force to make it cut, this isn't very much at all
-go as fast as you are comfortable, this is likely faster than anyone you have seen grinding
-don't go right to the edge, the knife doesn't blow up if you do, it just wastes the steel
-don't take the knife off the stone, cut up and down
-rinse/flush the stones off once the marker is removed
-mark in the edge again
-put a coin under one side of the sharpmaker, this will decrease the edge angle by ~1/2 degree on the rod nearest the coin
-grind on the 20 dps setting (now about 19.5) until the marker is almost removed right to the edge
-this is only a tiny angle change, it will happen very fast
-flip the coin, remark the edge and repeat on the other side
-continue this adding coins (or something similar) until completed
There are many reasons why this is much faster than doing one slogging session. It is precisely because people ignore basing grinding techniques that a lot of people think this is way harder/more difficult than it needs to be.
Plus people tend to grind really, really, really slow. It is very easy to make two passes (up/down) per second, I normally do between 4-6 per second and that is cutting both up/down, however you might want to work up to that, but 2 passes per second is easy to get.
If you employ a little technique then resetting the edge on the Tuff from 20+ dps to 15 dps won't take you half an hour. If you practice that technique a little and use a coarse benchstone vs the rods, you could flatten / zero the primary grind in similar time.
Note at very high grinding speeds, 4-6 passes per second, there will likely be a little rocking of the bevel, it will end up slightly convex and you run a high risk of scratches on the main blade grind. Again, you might want to work up to that.
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In short, the steel doesn't matter, grinding techniques are critical. And yes I have done it on many knives including 3V, 10V, 121REX, Maxamet and not only changed the edge angle but flattened entire blade bevels on knives which had thicker cross sections.
It isn't difficult, it doesn't require much skill or effort, just a little knowledge and it can be done far quicker for example than you could change a flat tire or other similar basic activity.
In fact if you actually read this post, then it is likely you could have had the first marker session completed by now.
