Re:Alternative Stepper Motor mountings, etc.

Rab,

Tygon is a trade name for a "medical grade" vinyl tubing (or at least
it's vinyl-like). I would only use this for light loads in a non
cutting setup. For learning it's fine. You can also use air hose,
automotive heater hose (these first two have cloth reinforcement in
the hose which will help prevent "windup"), urethane die springs,
or "hacksaw slit" aluminum or steel to make cheap couplings. Each of
these will have a greater or lesser ability to handle angular
mismatch between screw and motor. None will work as well(or as long)
as a properly designed and made coupling (except the hacksaw slit
metal, which is the same as what you buy, or CAN be...).

One thing to consider is the use of a timing belt from stepper to
shaft. Even if you don't need to 'gear up' or 'gear down', you can
use a 1:1 belt and IT will handle the angular variations.

If you have a rigid machine structure, you can use solid couplers.
Dave Rigotti at hobbycnc sells three for about 20 bucks. $7 ea., or
easily made. Now you just need to spend the time to get the motor and
shaft in alignment... Many small machines use this sort of
arrangement with good success.

Hope this helps.

Ballendo

> Is Tygon some brand name of flexible plastic ?
> Sounds cheap and simple compared with the helical couplers.
> rab

> > Even lower tech than a "slitted" coupler is a piece of Tygon or
> similer
> > tubing. A mm or so between shafts compensates for miss-alignment
> and with
> > fine pitch screws any wind up is small and elastic.
> > If you are worried about this check out the price on helical
> couplers :-{
> > Jeff