I literally get about 180 emails per day and I try to write articles based on what topic was most popular over the past few weeks in this bi-monthly
column. This past month I have had at least 30 emails asking about plastic shaft CTS pots for Fender guitars. The questions varied from “are they original” to “which models did they come in” so I will briefly cover what
No exact date is really known but based on my experience right around 1966 the first plastic shaft pots appeared in Fender guitars. Originally they were used solely on basses but metal shaft units were used at the same time. I have never heard of a solid reason why they changed or any advantage of the plastic shaft. I will say that mostly I have seen plastic shaft pots in Precision basses and not Jazz basses which is another strange phenomenon It seems from 1967 to 1972 was the major period these were used in basses. I would also like to note that plastic shaft pots were used at the same time as metal shaft pots so both are correct during that period.
The plastic shaft pots were always CTS with the first three numbers being 137. Fender at the time also used the Stackpole brand with a code of 304 but they were always metal shaft. Maybe plastic was just cheaper but who knows?
The second guitar plastic shaft pots turned up in was the Telecaster. Almost all Thinline Tele’s have these plastic shaft pots, again why is a mystery to me. Once again metal shaft pots are also found throughout out this period mostly on standard Telecaster guitars but you could find some plastic shafts as well. The time frame also seems to be about the same between 1968-1973. This was the Telecasters era for plastic shaft pots. Nothing is written in stone so some could show up as late as 1975 so don’t panic Another quick note by 1968 in many Telecasters, Fender started using 1 Meg pots instead of 250k but as usual with Fender 250k pots were still used and mixed over this conflicted period.
Finally as far as performance I can hear no difference at all. 250k or 1 meg pots with either plastic or metal shaft pots sound and function the same. I am not a technician and maybe on some level that’s inaudible they are better but no one I know tells me they hear the difference between plastic and metal shafts. I hope this helps a bit to clarify the plastic vs metal pots originality and any further questions you have I will be glad to answer.