To All,
I am looking for a little advice on sharpening. I am a beginner woodworker so please forgive me if this question is a waste of your time. I used to use sandpaper and granite to sharpen my chisels and irons. For course lapping I used the appropriate grit of paper (150-220) and then moved up through the grits (500,800,1000,1500,2000). Through the process of seeking understanding of sharpening, I have become obsessed with obtaining a mirror-polish finish. To that end I purchased some Norton 1000,4000,6000,8000 grit water stones. I seem to get as good, or better, polish from the 2000 grit sandpaper than from the 8000 grit water stone. To compare, I lapped an iron all the way through 2000 grit sandpaper and then used the 4000 grit stone and it dulled the finish, not enhanced it. Is there a reason that anyone can think of for this problem? The only thing that I can think of is that in the process of using the paper, the grit is crushed into a grit more fine than 8000. I see you masters use stones all the time and leave the paper for the course work. Please know that I have read a lot of articles and watched the videos on the topic. At your convenience, I would greatly appreciate any advice
Thank you for your time.
Replies
Dear Sir,
Well I think the issue is language. What one manufacturer of sand paper thinks of as 2000 grit may not be coarser than a 4000 grit stone. The issue is really the size of the particles in each. If you're getting a duller finish with the 4000 grit stone then it is coarser than 2000 grit sandpaper. So the micron size of each particle is the critical issue, not what the manufacturer calls grit.
I have no side by side information for you, unfortunately, on this. I'll have to do some checking but you have the verification of this theory in front of you.
Now the other potential issue is as you mention. It may be that as you wear out sandpaper the particles just keep getting finer and finer. So if you start with any grit of sandpaper, when you finish it's not the same grit. It's worn out. Not so much on a water stone. The slurry of course is a finer grit made up of metal particles and worn away stone. But the stone itself is always that same grit whatever it may be. In essence then I think one could say it's a truer grit. [My apologies to John Wayne.]
As for what experts use, their purpose in sharpening is to put an edge on and get back to work. Looking for a mirror finish is not useful to them. A good enough edge done quickly works far better than a supreme edge taking twice as long to do.
Personally I don't like sharpening. I like the results and try to get them as fast as I can. If you're obsessed with a mirror finish then go to an automotive paint store and get some real sandpaper. Something in the 10,000 grit range and knock yourself out. But if you want an edge that will work, live with the imperfections of a "scratchy" finish. Have fun.
Gary Rogowski
The Northwest Woodworking Studio
A School for Woodworking
Portland, Oregon
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