Re: : linear bearing based on ground flat stock

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Graham Stabler" <eexgs@...>
wrote:

>
> --- In CAD_CAM_EDM_DRO@yahoogroups.com, wanliker@ wrote:
>
> > If two edges of the bar are mounted vertical
>
> that's what I don't get, which too edges? Are we talking about

square

> bar or are we back to rectangular?
>
> > Why would that be? To rotate around the bar, with two V pulleys,
> you >would have to deflect two surfaces where the pulleys are

riding???

>
> Not rotate around the bar but rotate in any of the other

directions in

> particular along the axis (read axle) you get if you draw a line
> between the two rollers. You only have two small V's of contact

and

> although they will give some constraint in that axis I don't think

it

> will be very stiff and they will act as rather good levers I think.

V-track rail systems use opposing rollers. There is a preload
between the opposing rollers to prevent the roller from riding up on
the sides of the rail angles. With a preload, there is little or no
twisting of the trolley and it becomes very stable ( 4 total rollers
and two parallel tracks). Connect two trolleys with a beam to
create a gantry, or use one alone for a hexapod strut.

Fred Smith - IMService
http://www.cadcamcadcam.com/hobby