Join Date: Dec 2000
Location: Toronto, Ontario, Canada
I believe those might be banjo-style tuners with the stoppers on them (forget the brand name of those), to allow fixed twist stop points, allowing one to set up a different tuning which can be tweaked in at a moment's notice.
It's a country musician's trick originally, as I recall, putting these onto a guitar. The late Waylon Jennings always had those on his Teles' low-Es, set to stop at D.
It predates the Hipshot tuners with the levers - they strick straight out the back (if you've seen a banjo, you'll know what I mean). I guess this allows someone to use an alternate tuning at any tuner without bumping into another peg - that could be a problem with a tuner other than the low-E on a 6-in-line.
I remember a pic of another younger country player whose Tele had one on the low-E and the B strings.
... for what it's worth.