Hello, I'm new here and was hoping someone can answer a question for me. I have looked through the pdf owners manual online for this mower and cannot find the answer, so I'm hoping I can find it here? I have an Ariens RM1330 Riding mower. I think it's a 2003? It has a single nut underneath that is holding the the blade on. I have looked everywhere and cannot find out what size nut it is or if it's SAE or Metric? My SAE socket sized 1-1/16 is too small and 1-1/8 is too big? I was able to use a crescent wrench to tighten down and then measured it after I took it off the nut and it measured 1-1/16th to 1-1/8, I measured the nut itself and it was also that size, so I got those sockets and one is too big and the other is too small. I then tried a 27mm Metric socket as it was the biggest I had and it was also too small. I don't know if this nut is SAE or Metric and I need to get the blade off. If anyone knows the exact size of the nut that holds the blade on please share. I was using a 1/2 inch drive, if that makes any difference. Thanks everyone, and Hello from Iowa!