Hi Greg, Does anyone make reproduction parts for these reproducers? Steve
: [Phono-L] Columbia BC friction wheel drive> > Ron, it's difficult to explain the BC friction wheel driveshaft system > without pictures or handwaving :o) The drive train begins with a > gear-driven piece of metal tubing which is enclosed in the stationary outer > housing which is fastened to the gear housing casting on the side of the > machine. This first piece of tubing (call it part 1) rotates but does not > translate axially. Inside this rotating tubing is the brass coupling sleeve > (part 2) which can rotate and also slide along its axis. And inside the > brass sleeve is the solid rod (part 3) which connects with the amber wheel. > This part 3 rotates and also slides axially. Part 2 has two slots, > diametrically opposed and milled into its outside surface that run almost > the full length of the part. Part 1 transmits its torque via two setscrews > which extend inward from Part 1 into the slots milled in part 2. (Access to > these screws is via a hole drilled in the stationary outer tube.) This > allows Part 2 to be rotated by part 1 and also to slide axially inside part > 1. Part 3 has a "T" shaped fixture at its end that engages two longitudinal > slots milled INSIDE of part 2. This is what transmits the torque from part > 2 to part 3 and also allows part 3 to translate axially. The slots inside > of part 2 do not extend all the way to the ends of part 2. When part 3 is > pulled along the mandrel with the reproducer, its T fixture hits the ends > of the slots inside of part 2 and thereby drags part 2 along with it > axially. All this assemblage has a purposefully sloppy fit to allow the > amber wheel end of part 3 to wobble around radially so it can follow the > stylus assembly as it is raised and lowered from the record surface.> > Clear as mud? Again, it's hard to envision what's happening without > seeing the structure in detail. But maybe this helps understand it.> > Greg Bogantz
