On 2010-07-29, Pete C. wrote:

RogerN wrote:

"Ignoramus6705" wrote in message
...
My friend told me that he saw something written somewhere that
Bridgeport Interacts cannot mill (bore) a precisely round hole,
because of stretch on the servo motor timing belts. What do you think
about this statement.

i

I would think it is minimal since an entire turn of the handwheel is 0.2" or
so. I would guess belt stretch to make less than a half thou difference.
But if it does affect your parts, you have the capability to put DRO scales
on your mill and use them with EMC2 instead of the motor encoders. That's
what my mill has, an Anilam control with Anilam DRO scales , the motors have
tachometers on them, they are stable even with backlash.

Have you found me a Syncrowave yet? :-)

RogerN

He could also move his current encoders to be directly connected to the
ballscrews, eliminating any possible belt issues from the positioning
accuracy. He would cut the counts per inch in half, but I think it's
high enough not to matter.

Early on I have decided not to alter the hardware of this mill. What I
am doing is relatively simple. Changing hardware is complicated and
will ultimately ruin this mill due to my incompetence.

i