In preparation for repointing an outside wall I followed a neighbours advice and got hold of a couple of mortar rake bits to "use with an angle grinder" he had said. He has finished his walls to perfection but he's now vanished back to the UK. My angle grinder appears to have a 5/8" shank and I can only find 3/8" or 1/2" chucks. I need to be able to use the angle grinder to stand up to the sideways torque raking the mortar may require. the best that Ebay comes up with are 5/8 to 3/8 microphone stand adapters which look like a much finer thread.