Over on my earlier thread about hand planes, you all stressed the importance of blade sharpness in plane irons, and Jay got me to thinking of my abrasives in terms of microns. And this makes so much sense and really levels the playing field as far as abrasives are concerned.
I've done some research and found some discrepancy in these grit/micron charts.
1) I use Norton waterstones, 1000x, 4000x, 8000x. After Jay mentioned that he goes down to 0.5 microns with his plane irons, I was a bit concerned that my Norton 8000x wasn't giving me the best edge I could get, considering I will be planing white oak timbers. Nortons site lists the 8000x as 3 microns, while other charts list it as 1.2 microns. I see that some charts go by average particle size in the stone, and some go by the largest particle size in the stone. Any thoughts there on potentially clearing that up?
2) Also, I read where you can calculate approx. micron size by dividing 12,500 by the JIS grit standard (Japanese Industrial Standard) listed on abrasives. Any validity to this?
3) I recently bought a Sigma Power Select II ceramic 13,000x stone, but Lee Valley does not list it in microns. I've seen others say it is between 0.5 and 0.78. Sigma's 10,000x is listed at 1.5 microns, so I'm thinking the 13,000x ought to be under 1.0. Anybody have this finishing stone and know it's particle size in microns?
4) So my last question (ya right). Assuming my Norton 8000x really is 3 microns, is it too big of a jump to go to the Sigma 13,000x? Should I get another stone to fill that gap?
On a separate note, like some others here, I've had some down economic times recently and had to let my Guild membership lapse. But I was so impressed with the very helpful responses to my plane thread that I have since re-joined and am once again a proud Guild member. This forum has been an incredible source of info for me over the years, it's the very least I can do to give back. Thanks to all.
