I have a 20" Powermatic 3 (27 knife) thickness planer. I also have a grinder that attaches to it to grind my own knives. I am experiencing a lot of difficulty in finding a replacement grinding wheel for this machine. The wheel is pinkish brown in color, should have an OD of 6" max, and here's the kicker, an ID of 1 1/2". Thickness is 1/2". There seem to be lots of 1/2" to 1 1/4" ID options but not a single one with an 1 1/2" center. I really appreciate hearing from anyone who can direct me to somone that can supply the wheel I need. Thanks in advance...Fred.