On Fri, 30 Jan 2015 08:07:40 -0600, Ignoramus8636
wrote:

On 2015-01-30, Lloyd E. Sponenburgh lloydspinsidemindspring.com wrote:
Um... I didn't say they were. They can be made INTO servos quite easily,
and if you have an application that won't mind the inherent backlash in the
geartrain, they're quite powerful and quite inexpensive for the torque
they'll put out.

My own thinking is, if you are smart enought to make a servo out of a
wiper motor and adapt it to a milling machine, you should be able to
make enough money in less time to simply buy proper equipment.

i
+2 on that. Decent low cost steppers af reasonable power are readily
available at reasonable cost, and stepper drivers are likewize easily
available. When you are done you have something that works properly
and looks like it will.

To put a decent decoder on a wiper motor takes some hacking. Do you
put the encoder on the motor shaft, or on the output gear? On the
motor shaft gives much higher resolution, but requires a lot more
hacking (physically) to get to the motor shaft. - and then it is all
exposed unless you build a housing for it. Or are you talking about a
circuit to determine the revolutions by reading the waveform from
commutation? If so, even the big manufacturers can't seem to make THAT
work reliably..