Yashica AF Lens Question

I have a modest collection of Yashica AF cameras and lenses. To round out the outfit, I decided to get the 60mm f/2.8 Macro lens. I may have made a mistake by getting one for too low a price. When it arrived yesterday, the manual focusing was very stiff. There is a small chip at the end of the outside of the barrel so it may have suffered impact damage of dome kind. I had to pick up some things from my repairman this morning so I brought the lens along. My first thought was that after all these years, the lubricant might have dried out. My repairman thought the helical mount may be made of plastic and might not have ever had any lubricant. These are screw driver lenses so there must be some lubricant somewhere. I've never seen the inside of one of these Yashica AF lenses. My repairman will take a look. Are the helicoids all plastic? I have a number of Vivitar 100mm f/3.5 Macro lenses. They are known as the plastic fantastics. So far not one of them has ever failed me. I'm not sure whether they have any metal in their helicoids. They aren't as sturdy as a Kiron 105mm f/2.8 Macro but they are much lighter to carry around and are decent performers if stopped down even a little.

Too bad about the Yashica AF macro, I have few non macro for Yashica AF, not my fav camera but the lens lens are very sharp. I have a Vivitar S1 macro 90mm and the 90 to 180 flat field, but not the 100 .8 macro, as fair as I know none of these lens were made in Yashcia AF mount, I think there were very few 3rd party lens made for AF lineup as it was on the market for such a short period of time. I do have Sigma 50 and 100mm macro in Minolta Af mount, pretty good. The sharpest of the lot is the Vivitair 90 to 180 flat feild. Mine is in Minolta MD mount, heavy breast but really sharp from 80 to 180. Is your Vivitar 100 macro in AF mount?

If the manual focusing is stiff, then the AF will have a problem as well. Sounds like that "impact damage" theory has some evidence. First, I'd move this thread over to the REPAIR SUB-FORUM, and you could also try the Yashica FORUM. Lots of knowledgeable, nice, Yashica geeks over there:

https://yashica.boards.net/

I have most or all of the macro lenses Paul mentioned and many more. My 90-180 Vivitar Series 1 is in Konica mount. I wouldn't mind having one in Canon FD mount but last Fall I got a 70-180/4.5-5.6 Micro Nikkor AF D and I am gaining some experience with it. It works nicely with my N90S cameras. While I wait to hear about my 60/2.8 Yashica AF lens, I got the short Yashica AF extension tube. Can the Yashica tubes be stacked?

While I wait to see what becomes of my 60/2.8 Yashica AF lens, I bought the previously mentioned extension tube and a T to Yashica AF adapter. This will allow me to attach any number of non-Yashica macro lenses, without AF or auto diaphragm operation.