I just received this link to a forum thread devoted to the Columbia BC. Reid Welch has fitted new friction parts to a BC and has had good success with them. He even includes a video of his machine in operation! The only one on the internet, I think. There's hope for us BC owners yet! Good stuff. Enjoy:
http://www.forum.condorcup.com/viewtopic.php?f=7&t=20&p=59#p51 Greg Bogantz ----- Original Message ----- From: <[email protected]> To: <phono-l at oldcrank.org> Sent: Sunday, August 31, 2008 5:16 AM Subject: Re: [Phono-L] Columbia BC friction wheel drive > paul baker used to restore these but he takes a long time to do it > > > In a message dated 8/30/2008 3:49:30 P.M. Eastern Daylight Time, > steve_noreen at msn.com writes: > > 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 s > tationary 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 > _______________________________________________ > Phono-L mailing list > http://phono-l.oldcrank.org > > > > > > **************It's only a deal if it's where you want to go. Find your > travel > deal here. > (http://information.travel.aol.com/deals?ncid=aoltrv00050000000047) > _______________________________________________ > Phono-L mailing list > http://phono-l.oldcrank.org
