Originally posted by ChatMechant What would I need? I also build/repair vintage tube microphones so I have some tools like small screwdrivers, tiny needlenose pliers, nothing lens-specific.
An old toothbrush
A friction tool to get the "name" ring off
Screwdrivers for slotted screws like in my photo
Very small slotted screwdriver for "grub" screws like in the ring with depth of field markings
Maybe a lens spanner or improvised lens spanner
Solvents and fungus killing stuff.
This guide is for a very similar lens:
https://www.pentaxforums.com/forums/114-maintenance-repair-articles/217082-ta...egreasing.html When you get to step 3 in that guide, you can see a few slots for a lens spanner around the front element. Use the outermost slots to unscrew the whole front group. That gives you access to the top of the aperture blades.
At this point you have to decide how much more disassembly you need to do to free the blades. It shouldn't be that difficult to remove each blade and lean them all. I know I was able to figure it out myself in 2006 when I did mine, but can't remember exactly how it goes. Focus the lens so the front barrel protrudes (not so far that it falls out) and look for grub screws on the outside of that barrel. Reassembling them needs a little patience but there are only six. The worst-case scenario is not oil, which cleans up, but rust sticking the blades together. They are so thin that rust can make holes or deform them. Mine had just a couple of rust spots which scraped off and haven't recurred.
Step 9 in that guide is not necessary if your focusing ring works OK.