|It's been over a year since I wrote up my take on diamond sharpening. Since then we have moved, my stones were packed, lost, found, unpacked, shifted about, and finally are sitting in a box next to my desk. More importantly, the diamond stones have worn in a bit and cut smoother, and after going back and forth I think I finally have settled on a sequence that not only works well for me, is faster than what I used to do and has become my new methodology. |
This is big news for me. This is the fourth major change in my sharpening practice since I started sharpening anything and being fairly traditional I don't change things for the sake of changing. My technique has not changed. I still find sharpening jigs to finicky and slow, and I hollow grind everything I can. What has changed is my choice of technology. Instead of water stones that need flattening I use diamond for all except the last two steps.
Step one: Fine Diamond Stone. - In the picture I have a double sided DMT 12" diasharp continuous stone in DMT's magnetic base. If my edge was damaged I would regrind the tool. Without a grinder I would use a coarse diamond stone to remove the damage. The 12" long stone is overkill. The 8" stones are fine, and I think if I use the longer stones more I will have to get used to making a longer stroke when sharpening because otherwise it is a waste. However, if you use a honing guide the extra length will be very handy as it leaves room for the guide. I use a little water for lubrication. I was teaching a class and had the magnetic base handy, but normally the non-skid mat is fine(but keep the mat dry). The fine diamond cuts fast enough so I can get a wire edge with no trouble and very fast. I do the back, then the bevel, and work the tool until I have raised a wire edge or burr.
Step two: Extra Fine Diamond Stone. I chase the burr, refine the scratch pattern.
Step three: 8000 Grit Norton Stone. I know Norton stones are out of fashion but they do a really great job with A2 and D2 steel. Being friable they cut much faster than harder, less friable stones. I find that a regular finishing stone, like the Norton 8000, gives me a smooth, sweet edge that I just can't get with even the finest diamond stones. Diamond crystals are sharp and stay that way and I still get more of a scratch pattern than a polish with any fine diamond stone. (Diamond paste does give a polish but I don't see an advantage in this case). I do soak the 8000 stone, but because the edge is basically ready for final steps there isn't much wear and tear on the stone and only a little maintenance for the stone is needed. With the 8000 I chase the burr until I can no longer feel it. If I am adding a microbevel I will then do a half dozen strokes to raise a new tiny burr and chase that. When I cannot feel the burr I stop.
Step four: Strop: For best results strop on a PLAIN leather strop, not a strop covered in honing compound (which has its place but not on straight, hollow ground tools). As I strop - about 10 fast strokes on a side, repeated about 3-5 times - you can feel the edge become smoother, sweeter, and generally sharper.
I know I have completely glossed over the details of holding a chisel, how to strop, and etc, for detailed sharpening instructions click here (Just use diamond stones instead of the Arkansas stones in the article).
I don't use my diamond stones to flatten the 8000 grit stone. I use a ceramic flattening stone. The problem is that flattening waterstones erodes the plating holding the diamonds on the stone. We do stock special "hard coat" diamond stones made for lapping waterstones which are great, large, but too coarse for normal sharpening (and not inexpensive). We also stock finer hard coat stones for regular sharpening but I would still want something coarser for flatting a stone.
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