[Just1MoreDave]

Interesting. You can improvise a spanner by grinding down tips of scissors or needlenose pliers, but you have to be pretty confident they won't slip. Usually the slots are right next to a lens element, so slips are bad. I tried to see if that's how mine was built and the rear group is in there pretty good. I decided to leave it alone. You can get a little more working room by removing the light shield, three tiny chrome screws 120 degrees apart below the bayonet tabs. Two screws are close together near the aperture lever; you only need to remove the one farther away from the lever. These screws are not as picky about screwdrivers as the mount screws, but they are tiny. The first screwdriver I picked up out of the clutter was a Craftsman #000 that I got recently at Sears.

I have one with a separated front element so I'm interested in buying this lens if you want to sell it.