I'd never used a Japanese water stone before today. Also, I'd never used or prepared a card scraper.
I had heard water stones were softer than India or Arkansas stones, but I also heard the Shapton stones were an improvement, especially the ceramic. So I got ceramic.
Flattening the edges on brand new card scrapers took what I thought was a really long time(20 minutes solid of vigorous sliding for two scrapers, two 6" x .030" edges per scraper) to get all evidence of machining off of the edges. Also, I left a lot of grooves in the stone. Could I have avoided this had I rounded the corners of the scrapers? Is there any reason not to?
Despite the perceived long time, I knew I was removing metal from the scrapers because the water was getting thick gray and I had to keep spraying the top of the stone to keep gray sludge from clogging up the works. I think at least some of the sludge could have been from the block of wood I was using to keep the scraper edge at 90. I guess maybe I need a 90 degree honing guide with wheels! lol
Attachment 381794
I was using the 1000 grit "ha no"... whatever it's called. K0702.
When I watched William NG and Matthew Cremona sharpen card scrapers, I got the impression that things would be a lot faster. Matthew spent a total of like 20 seconds on one edge after filing before going right to a 4000 grit stone, before finally moving on to an 8000. I was using a stone with a quarter the grit rating, and was going for 15 times longer. And to be honest, the cards looked flat when I started, they just had very, very light milling marks. I suppose I could have filed them, but William Ng says no do.
William says he doesn't file his scrapers because it's just like taking a file to your wood. regardless, William didn't take very long, either. He started off on a 1000 stone just like I did. Might even be the same stone I have. Same color and general shape. Anyway, he spent just a few seconds at 1000, then moved onto what he called a 4000 grit "polishing stone."
When it came to burnishing, I had to use a lot of pressure to get anywhere. Both Matthew and William emphasized that lots of downward pressure was not necessary. I absolutely did not find that to be the case. I did eventually get my burrs with mega pressure. I wasn't using a purpose-made burnisher, I was using the lower part of a Woodcraft cheapie chisel handle. They claim they're hardened to R 59-63, and the card scrapers(Crown) claim they're R 40-42. I don't know if that part of the chisel is that hard, of if it's just the blade area. I did read a review on the scrapers by someone who claimed the scrapers were really hard and burnishing was really difficult compared to their other scrapers, so I'm possibly not alone, there.
So I need softer scrapers, a proper burnisher, and to flatten my water stone. I ordered an Atoma 400 diamond plate to do that. Not a true lapping plate, but I can't afford one at the moment.