Re: [CAD_CAM_EDM_DRO] Re: I need some feedback on using wire rope for driving...

Dave Halliday wrote:

> I am thinking that you would have to go through some extreme gyrations to
> get this to work over more than a foot or two of spindle travel.
>
> You can get Acme Threaded rod in large diameters but imagine the inertia of
> a 15" by 2' bar of metal.
> http://www.keystonethreaded.com/acme.htm
>
> I would use thick-wall Schedule 80 PVC pipe with a belt reducing system to
> the motor.
>

If you are using something like 1"-8 all thread for the spindle,
consider making two of them. Let's call them A and B. Cable 1 goes from
A to B, Cable 2 goes back from B to A. A threaded follower (think a nut
with extensions to hold pulleys) goes on each spindle and guides the
wire rope into the grooves. With the cables parallel to the spindle,
each turn of A moves its follower to the right a small fraction of an
inch and moves the follower on B the same distance in the same
direction. The cables move PI * the spindle effective diameter plus or
minus the pitch per turn, so for a 1"-8 spindle, 3.14159 inches plus
(or minus) 1/8". No complex mechanism, just two spindles and two
followers. The followers will ensure that the rope will lay in the
grooves (threads). Of course tension is maintained and the rope has a
predictable movement.

Just another way to skin the cat.

--
David G. LeVine
Nashua, NH 03060