Re: gearmotors,encoders

--- In CAD_CAM_EDM_DRO@egroups.com, jmw@c... wrote:

> Mariss, wow, there's nothing like real data. Let's say a solid lead
> screw 1.25" in diameter is five times stiffer than your test bar
> (tube). That'd put things kind of on the boderline in terms of
> loosing a count with a motor in the 250 in/oz range and operating

at

> capacity. I guess things are a little less favorable when the

torque

> is applied suddenly?
>
> --Jack

Jack,

Hi, unless I am missing something here it should go the other way. My
torque wrench is calibrated in in/lbs. The reading was 800 in in/oz.
Also in comparing tubing versus a solid shaft, most of the stress
(and resistance to torsion) is concentrated near the surface. The
very center of a solid shaft contributes no torsion resistance at all.

Torque is torque; it makes no difference if it is suddenly applied or
is static. The deflection will be the same. The only effect of time
(rate of torque change), is a second-order efect. It will excite a
mass-spring system into resonance (ringing).

Mariss