Re: Alternative Stepper Motor mountings, etc.

Dave,

How are you handling the backlash on the nut to the threaded rod.
I was thinking of using bog standard M6 threaded rod for it's 1mm
pitch, is there a big advantage to ACME rod ?

Rab

> I am doing the prototype with 1/2-13 threaded rod, 10 feet long.
> with plans to use 1/2-10 ACME on the final unit. (still looking
> for 10 ft ACME rod)
>
> Using a 10 TPI for discussion, my stepper does 200 steps per
> revolution, and with 10 rotations per inch, each rotation is 0.1"
> travel. each step therefore is 1/200 of 0.1" or 0.005" per step.
> Simple math.
>
> I looked at using a smaller stepper (I'm cheap) and gearing
> up to get better torque. a 6:1 gear arrangement would allow
> me to use tiny motors, but travel time would be too long.
>
> My gear train design would use about $45.00 in
> spur gears, require lubrication, and put is gear slop.
> and then there is the cost of manufacture, a few hours at least.
>
> For the money, and speed, and time savings, I am going with
> a larger motor and direct connection.
>
> I am looking for an overall accuracy of 0.005" in the final
> unit, so all I really need to concentrate on is one connection
> that being the ACME rod to the nut. In my application, I am
> more interested in repeating a location, than overall accuracy
> from end to end. If I neeed metter accuracy, I'd go with

ballscrews.

>
> Hope this helps.
>
> Dave