Ignoramus6705 fired this volley in
:

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 think that for any given feed vector, you could calculate (or measure
empirically) the stretch, and have a lookup table that adjusted the feed
to compensate. That would probably be a difficult programming job, but
anything is do-able. Back in the early 80's, I wrote Z-80 code that
would allow a bar code wand to scan a code at _widely_ varying speeds
within the body of the symbol (over 20:1 and varying rapidly), and still
decode it reliably. This is that sort of task. A wide range of feed
rates and feed depths would need to be accommodated, and you'd even have
to account for materials in the adjustments -- but it's just software.

I'm not sure what EMC enables you to do in that respect, but since it's
open-source, it's extensible.

The stretch on a belt is not immeasurable, but with modern Kevlar
reinforced belting, I think it would be minimal (supposing the belt is
not used near its design limits). I don't think the BP guys would have
liked not being able to mill round pockets. No... I don't think they'd
have settled for it, at all. Probably, their belts weren't 40 years old,
either G.

LLoyd