side loads ( was Beginners screws ( was ACME ( was Re: leadscrew,

--- In CAD_CAM_EDM_DRO@yahoogroups.com, CL <datac@l...> wrote:

>
>
> alex wrote:
>
> >Thank you, Ross - I'm more or less sure now what to do.
> >Will place sprocket directly on the shaft of stepper, then pull

carriage in

> >a loop by the chain.
> >
> You might want to slide that sprocket in a little further so you

can at

> least get a smidget of support on the end of that motor shaft with

an

> outbound bearing....
>
> It still is not enough, but that would be better than nothing.
> Most steppers are not made to take much of any side load on their

bearings.

>
> Ultimately, you need to put the sprocket between two bearings on a

shaft

> that is driven direct by the stepper with a Helical coupler.
> Or, mount the motor to a short section of square aluminum tubing

with a

> bearing on each side. One bearing can be right on the motor shaft,

the

> other on an extension with the Sprocket.
>
> That obviously takes more work.
>
> Then again, if motors are cheap enough, just replace the motor when

it

> goes "south".
>
> Chris L

A simple pair of bearings on a plate would allow for one to make an
adjustment frame that rotated around a point. that way, the motor
would not be involved with side loads, and motor access would be
simple without taking apart the whole machine.