|Forum topic by bob44||posted 09-23-2010 10:11 AM||1419 views||1 time favorited||1 reply|
09-23-2010 10:11 AM
First, I should give an introduction. I sharpen hundreds of kitchen knives and wood working tools, as well as some straight razors for personal use and restoration projects. It started out as a hobby and I mainly sharpened tools for family and friends; more recently, I’m trying to start a small sharpening business on the side until I finish school and start a real career. Although I use a belt and bench grinder, I do most of my sharpening using bench stones (This might change if business picks up). For polishing, I use a shapton glass 4000 and 8000 grit stones, followed by a .5 micron chromium oxide and .05 micron alumina polish pasted strops. I found the .05 micron alumina polish on a metallurgical supply company’s website; its intended use is for polishing semiconductors, however, it puts a wonderful edge on straight razors. This system allows straight razors to easily pass the hanging hair test and wood working tools and kitchen knives to pop hairs off like a razor blade. I’m pretty much content with this system, although I might experiment with lapping film and naniwa super stones just for fun. The problem I’m having is finding the best course and medium hones for shaping blades and grinding new primary bevels.
With regard to course hones, I’ve used Norton course silicon carbide stones saturated in kerosene and DMT course and extra course diamond stones. Both these systems seem to cut at the same speed. The problem with the oil stones is that when they do dish out, they are a nightmare to flatten and I have to clean the oil off tools before I move on to the Shaptons. The DMT stones begin performing well, and then decline as the diamonds wear off. I need to replace them every three to four months. After reading about how fast water stones cut and how they are superior to oil stones, I bought a set of nortons from 220 grit through 8000 grit. I soaked them in water and lapped them. The course stone cut much slower than my silicon carbide oil stone and did not work up a nice burr. The finer stones did nothing to improve the edge. I sharpened the same knife to a razor edge on DMT and shapton hones to convince myself there was nothing wrong with the steel or my technique. Next, I ordered a 220 grit glass shapton and a 220 grit naniwa superstone. I’ve experimented with these stones on a couple knives and a beat up chisel. Neither one of them cut as quickly as the diamond or oil stones. Also, I never get nice clear burr like I do with the other stones. It seems strange that three different brands of water and ceramic stones would perform so poorly compared with oil and diamond.
My questions are:
1) Am I doing something wrong!
2) Do water stones give an easily felt burr, or do you have to rely on other measures to see if you have ground a new edge?
Thanks for any advice,