[TriLUG] Far, far OT: Thin-wall bushings

[Brian]

I knew there'd be some knowledge to glean on this list!  Here're some 
responses to questions a couple folks asked.

On 9/10/2014 2:41 PM, Joseph Mack NA3T wrote:
> I don't know if the tubing is as thin as you want. Can you turn the
> shaft down?

Not without a great deal of trouble; it's the armature of a stepper motor.


On 9/10/2014 11:17 AM, C TC wrote:
 > Does it have to be metal? I've used delrin [...]

I'm concerned about rigidity.  I printed one out of ABS and it's got too 
much give; the gear wobbles.  Delrin is more rigid, but I'm not certain 
it's rigid enough.

The application is the Z axis of a DIY CNC drill press; that is, the 
up/down movement of the drill arbor.  I have modified a MicroLux 
miniature drill press by removing the return spring and replacing the 
lever with a worm gear; the worm itself is the offender with its 6.5mm 
bore.  There's a considerable amount of force involved, and I'm right at 
the bitter edge of the motor's torque capabilities, so I'm trying to 
eliminate as much torque-eating flex from the system as possible.  I may 
end up having to find a stronger stepper anyhow, or adding additional 
reduction gearing (which might provide an avenue around this whole issue).

Thanks, everyone!

~Brian