Thanks, Booli. I'll go to the ranch supply store tomorrow. Knowing what the material is helps--vs the brand of tuner. I love this group.
I'm glad to help.
FYI: IIRC, "Delrin" is some variant or more modern polymer of old-school Dupont 'nylon' and is used a lot in friction fittings where a certain balance of slip vs. grip is needed, like in instrument tuners, and I've seen it used on geared tuning machines of all sorts (near the tuner button) as well as in all manner of better friction tuners (which I still cannot use).
I have taken apart and rebuilt over a dozen different friction tuners, and tried to make them work easier, i.e., smoother to turn, yet tight enough NOT to slip, and have had mixed results. I do like them for their light-weight, but the fiddly nature of using them drives me crazy...
Thus, from my hacking with trying to improve them, I have come across a variety of things, such as the Delrin, ABS, PLA, leather, cork, felt, cardboard, rubber and metal washers...and some other materials that I cannot remember at the moment...