Originally Posted by
redbang
Most of the modern two wheel grinders come with wheels that are too"hard". By that I mean that the matrix which binds the all the bits together is designed to make sure the wheel doesn't wear too quickly. Consequently the wheel tends to clog up quicker and doesn't grind particularly well, but it lasts for years ! If you are going to be sharpening expensive good quality tool steel, you need the softer matrix as recommended by ebf and PaulNZ. These wear a bit quicker but expose fresh cutting edges on the matrix which make them more efficient at cutting the hard materials and you're not likely to burn the steel which is easy to do if you try and "force" the cheap hard wheels. The soft wheels are easier to dress as well, it takes a lot lighter force to get the wheel squared up. Just my 2c worth :)