[Phono-L] Columbia BC friction wheel drive

[Greg Bogantz]

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: <Zonophone2006 at aol.com>
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
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