another aspect to having jobs being very long is how deep you cut on each pass.
I’ve seen recommendations of the limit being anywhere from 1/2 bit diameter to
2x bit diameter as a general rule.
Bar tends to be extremely conservative on this and cut 0.2" per pass, so it
takes lots of passes to go through things, but he has also done tests where he
cut all the way through 3/4 plywood in a single pass.
This is an area we don’t have enough testing on. As the cuts are deeper, the max
feedrate that will work is going to drop, but is it going to drop just a bit (in
which case the total job time can still be faster), or is it going to drop a lot
(in which case the total job time may end up being the same or slower)
the machine is limited by the speed of the motors and the force of gravity, if
the motors are pulling on the sled, the only limit is the speed of the motors,
but if the motors are letting chain out (especially in the lower corners) the
limiting factor is the force of gravity and the only way to improve the speed is
to change the angle of the machine and the angle of the chains.