Some of my 35mm Nikon lenses have stiff focusing helicals. I dont know what makes them stiffage doesnt seem to matter (all those affected are over 20 years old, but some over 30 are just fine), nor does usage (some I havent used in years are just fine), and theyve all been stored the same. One in particular had become so stiff I quit using it. The obvious answer would be a trip to the factory repair center. But the bill would be more than the lens would be worth. So I tried something. By extending the lens to close focus and looking in from the back, I could see a small portion of the entire circumference of the helical. Grease was present, and it didnt seem dry. But I figured some additional lube might help. So I picked up a hypo and long needle, and loaded it up with a thin clock oil Then very carefully, keeping the needle at the juncture of the helicals, I placed a micro-dot of oil every half-inch or so around the circumference. I probably used no more than one good drop on the entire lens, and I was extremely careful to keep away from the diaphragm blades. Then I ran the focus back and forth to work it in, and left the lens overnight pointed down. It did help a little. The focus is still much stiffer than normal, but useable. Now Im looking for suggestions. Should I give it another treatment, or should I leave well enough alone? Or should I "bite the bullet" and have it done right at a repair shop?