I have posted in the past that I have used Pete Smith at Fotocamera Repair Service in Lake Worth, Florida (561-433-8434 or email [EMAIL PROTECTED]) to ai my Nikkor lenses with excellent results. Recently, a question was asked if anyone knew where to get original ai rings. I talked to him today, and he says he has original Nikon ai rings only for the following Nikkor lenses: 20mm 3.5 20mm 4.0 24mm 2.8 28mm 2.0 28mm 3.5 35mm 1.4 35mm 2.0 50mm 1.4 50mm 2.0 55mm 1.2 105mm 4.0 135mm 2.0 135mm 3.5 200mm 4.0 ED300mm 4.5 400mm 5.6 It would be wise to call or email him first to determine if the serial number of your lens matches the group that he can fit the rings to. He charges $22 just to mill the lens, or $50 to mill and install the original ring. He has done excellent work for me in the past and I can recommend him highly. He takes about one to two days to do the work. Hope this is helpful to those that need this service. Tyler Knapp Coral Gables, Florida