[Robotgroup] bead chain gears

[Gray Mack]

I thought using a bead chain might be easier than a
belt because you can cog it from any angle and
Breed&Co is a readily available source.

Last night I made an attempt to machine one on my
drill press. I don't know if it is that usable but it
is a pretty good first try. The next step is to meld
the 6 pieces of aluminum together. I tried PC-7 epoxy
compound but I am not sure it will hold permanently.
It's about an inch in diameter with 15 teeth. I will
bring it tonight.
-Gray

--- Paul Atkinson <pmatkinson at gmail.com> wrote:

> Rick,
> 
> I think Gray was looking for the gear to drive a
> beaded chain. Is there any
> chance the pulleys for the paper drive you mentioned
> are available on an old
> printer? I think I've heard it called a sprocket
> drive, because it drives
> pins that engage the holes in the paper.
> 
> Paul
> 
> On Wed, Feb 20, 2008 at 9:57 PM, Richard Abbott
> <dlluwh at sbcglobal.net>
> wrote:
> 
> > Gray,
> >       I just love printers. Even when they don't
> work, they can still be
> > of use. I don't know about any of the newer types,
> but the older ones had a
> > cogged belt that carried the print head back and
> forth. They are about 10"
> > or so long,and many of them come with a matching
> gear at one end, and one on
> > the drive motor. If you need more length, you
> might be able to splice two
> > belts together, and have your pulleys arranged so
> that they don't run over
> > your splice. Just a thought.
> >  Rick
> >
> > Gray Mack <gray_mack at yahoo.com> wrote:
> >  I still have not had any luck in making bead
> chain
> > gears. I want to use bead chain to get linear
> movement
> > from a pair of stepper motors in a frame.
> >
> > I tried PC-7 compound but it was too sticky to
> work
> > with and I tried clay, but its hard to get a good
> > round gear where the bead dimples align when you
> get
> > around the circle. I guess I could try measuring,
> > marking and hand cutting some plastic. Seems like
> I
> > need some sort of protractor vice thingy, but
> ideally
> > this would be a maker type project that wouldn't
> > require a machine shop to complete.
> >
> > Also I was trying to work with the small 1/8" bead
> > chain but I can get the larger bead as well. I
> went to
> > several Goodwills but didn't find the kind of
> > mini-blinds that have one. I guess I can press
> forward
> > with some rubber pullys for now to proof the
> concept,
> > I would just expect some amount of slip to occur
> over
> > time with that system.
> > Any suggestions?
> > -Gray
> >
> >
> >
> >
>
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