Back in the 1970's I purchased an electric Craftsman Die grinder for a job I was doing. Shortly after I found the matching tool post mount on clearance at Sears. I even still have the collet reducer to use 1/8 shank stones. They've been on the shelf ever since so last week I dug them out and modified the mount to fit the tool post on my lathe. I've never used a tool post grinder but I did some tests and I think it has possibilities. What I don't understand is what stones get used for what applications? I have a collection of both 1/8 and 1/4 inch shank mounted stones but no information as to what they are? Grey, Pink and sand colored. Any I found on line seem to come in sets and have no information as to what they are? I do know the pale blue ones are for polishing aluminum. Suggestions?