Ever have a stone that stops cutting?

[Evil D]

I'm posting this in off topic because it's Edge Pro related. I decided to fully resharpen my S90V Yojimbo 2 last night, because for some reason it just doesn't seem to get sharp like it used to. Of course I've questioned my methods, but in the past there have been other times with other knives and steels that if I just cut off the current edge by gently slicing into a 1k stone and then resharpen the knife, removing all that old edge was the trick.

Well, I feel like one of two things is happening here. Either 1) I've run into the hardest spot on this blade and nothing I have will seem to cut it, or 2) my Shapton stones have somehow lost their bite. Neither of these seems likely to me, but I can't wrap my mind around this. I've reprofiled S110V quite a few times, and I've done some very low angle stuff on 20CP while taking my Para 2 down to 20 degrees inclusive so I know my way around this type of steel. The stones just aren't making any slurry at all, and there's just the tiniest trace of metal in the water that I'm coating the stones with. This is highly irregular in my experience, as I almost get full on mud slurry even with S110V.

What could be going on here? I lapped all my stones before starting on this knife, I've tried 220 and 320 Shapton stones just to see if one was the culprit, I've even dug out my 320 Edge Pro stone and nothing seems to cut, so it definitely seems more related to the knife than the stones. The bevel is even taking on a shine like it's getting burnished. I clean my stone after making passes on each side, and I've lapped the 220 and 320 stones both twice now because I wondered if I had hit a bad spot in the stones or something, but nothing has changed. I'm about to switch to a different knife and see what happens.

[yablanowitz]

When I sharpen S90V, I always start with DMT Extra Coarse to cut a new bevel. The vanadium carbide volume in the steel is high, and I find anything softer than diamond to be a waste of time cutting it. In fact, when I was trying to find out just how hard vanadium carbide is, I found two abrasive hardness references online. One listed it as just below the aluminum oxide used for ceramic hones, the other listed it just above that hardness. Since I switched over to diamond hones thirty years ago, I haven't found a steel that gives me much trouble.

[Evil D]

Wow....so after posting this I kept working at it, then decided to lap the 220 again, and now it's cutting like a champ. Mud slurry everywhere, scratches on the bevel again. I then experienced the same thing with pretty much all my other stones right up to 16k. Seems this steel/knife is just clogging the pores of the stone VERY fast? Rinsing the stone doesn't seem to improve the situation much but a gentile lapping did the trick.

[Ankerson]

The reason why I use SIC for everything. :)

Makes fast work of any steel I have ran into, then once the bevels are set it's easy.

But yes keeping the stones flat and clean does help.

[Evil D]

The reason why I use SIC for everything. :)

Makes fast work of any steel I have ran into, then once the bevels are set it's easy.

But yes keeping the stones flat and clean does help.

Didn't you say those were Congress stones? Where can I buy them? And do they need mounted on blanks?

[Ankerson]

The reason why I use SIC for everything. :)

Makes fast work of any steel I have ran into, then once the bevels are set it's easy.

But yes keeping the stones flat and clean does help.

Didn't you say those were Congress stones? Where can I buy them? And do they need mounted on blanks?

Congress tools. :)

No, you would have to buy the blanks.

[Donut]

This is where you get them from.

http://www.congresstools.com/catalog/ca ... ory/?id=27" onclick="window.open(this.href);return false;

[Evil D]

This is where you get them from.

http://www.congresstools.com/catalog/ca ... ory/?id=27" onclick="window.open(this.href);return false;

Awesome thanks!

Congress tools. :)

No, you would have to buy the blanks.

Last question, do you get the 1/4 inch thick blanks or stick with 1/8?

[Ankerson]

I use the 1/8" personally. :)

[JD Spydo]

I had to think about this one for a while>> and I guess one good example I could come up with is Spyderco's great ceramic stones. I usually only will use any Spyderco stone for two and no more than three sharpening jobs and at that point I give them a thorough cleaning with Bar Keeper's Friend or other great cleanser. I find that for ceramic stones especially that they lose their uniform bite quickly if you don't give them a thorough, complete cleaning.

Also any of the natural stones like Novaculite, coticules and other natural abrasives also need to be kept clean frequently. I've noticed that Spyderco's FINE stones literally just quit abrading after two to three uses. It seems like the FINE and ULTRA FINE stones in particular load up quickly.

Diamond stones are the only ones I've used up till now that just don't need constant cleaning IMO.

[Evil D]

Yeah fine stones in general are going to clog more because they are typically harder material so they wear slower and they're made up of finer material so the pores are much smaller so it takes much less to clog them up.

[Brock O Lee]

My stock EP stones need regular lapping to restore their cutting ability, especially the 120grit coarse SiC stone that does most of the work during a reprofile. I usually start with a freshly lapped stone. I can sometimes feel it stops cutting before the bevel is set on a steel like S90V. At this point it just slides over the blade but there is no agression left in the stone to cut the steel. If I lap the stone it will cut like a champ again.

When I first got the EP a few years ago, I always thought lapping was just a way to flatten the stone again, but after using it for a while on these high carbide steels, I have learnt that lapping is essential maintenance on these stones to preserve both the flatness and cutting ability of the stones. I do not think the steel just clogs up the pores of the stone, but it also wears the sharp edges of the indvidual abrasive particles smooth.

I need to get myself some of these Congress stones eventually...

[JD Spydo]

Like I said in my previous post the diamond benchstones are the only ones I got that don't clog up after prolonged usage. But diamond is a completely different animal all together>> it's truly an apple versus orange comparison. Now there are natural stones and a few synthetic stones that won't clog up as badly if you use certain oils and lubrication products with them. But I personally hate stones that I have to use oil with because of the massive cleanup job you have afterwards.

I've yet to test drive the newer CBN stones so my jury is still out on those. But I've heard good about them and from what I have heard they have a lot of the characteristics of diamond stones. I have a feeling with all the nanotech innovations coming down the pipeline that we are going to see a new generation of abrasives and it will render a lot of the ones we use now as obsolete.

But I've resigned myself to the fact that if you want premium performance out of those great Spyderco ceramic stones you must pay the price of frequent cleaning. And it's really not all that bad>> just the other day I cleaned 3 of my Spyderco 302 Benchstones, all of my 204 Sharpmaker stones, my Doublestuff stone and another ceramic stone ( not Spyderco) all together and I timed it>> it only took me 16 minutes to get them all in tip top shape>> and the great uniform bite you get is well worth it IMO.