Failure to get sharp

RWL · 2003-10-05T16:01:47+00:00

This is a follow on to my progress in making some blades out of waterhardening tool steel.The blades have been ground to an angle of 20 ºBUT they don't feel or act sharp, unlike a commercial blade or asimilarly ground blades on a wood plane. The question is why won'tthey TAKE an edge (as opposed to why won't they hold an edge)I've looked at them under a magnifying glass and can't see anythingodd or different than a similar commercial blade I'm using as mymodel. The edge is coming to a point.One thing that I notice is that I never get a wire edge on the flatside when grinding or hand sharpening these. That is probably a clueto something.Having never hardened and tempered a tool before, I'm wondering if Idid something wrong. To recount the process I used. As best as I can tell, it's W-1 water hardening tool steel - my 1999MSC catalog lists it only as flat ground tool steel. It's the samecomposition as their drill rod which is listed as W-1.I heated the blank with a torch till it was red hot and it was nolonger attracted by a magnet. The metal is relatively thin at 1/8 inchthick, so I held it at this temp for no longer than an estimated 30seconds to one minute. After rapid quenching in water with astirring motion, a file would no longer cut the steel. I tempered ina toaster oven. Since I don't have an oven thermometer I had toguess the temp on the toaster oven was only close, and went on the lowside. The first blank was ground to its intended angle BEFORE tempering. Igournd slowly and no oxide colors developed on the blade edge as I wasgrinding. I heated it for 30 min at about 450. I could see thefaintest of yellow oxide color on the blank. I finished by handstoning the edge using a variety of methods - diamond, differentgrades of emory glued to thick glass. It's sort of sharp - but like adull plane blade. It just won't get sharp.The second blank I tempered before grinding it to an angle. In thisrun, the oven was set to 400 for 30 min, raised to...