Just take off material until you don't bind anymore. The pin holds the hex in place so it's not like the hex has to rest super close to the hub. I'm not sure what grit I used. I just have some of those Testors sanding films. I picked one of the middle ones and sanded until I had clearance between the hex and hub. I may have removed the whole raised area. I would have to take it apart to see for sure.