MPG wheels. This one controls the longitudinal feed, and this one
controls the cross feed, very similar to the manual wheels that were originally on
aluminum faces where the switches and the wheels attach to an those attach
to a wooden box that clamps onto a stepper motor that's connected to the
conversion kit and that pushes up against a plate that's also on the
conversion kit. The face plates will be milled on the CNC mill and it starts
while the interior small holes were made by interpolating a 1/16 inch end mill.
wheels. They have differential quadrature output which means they can
be used in a way that's immune to a common mode noise and that you can also
achieve 400 pulses per revolution. However, the detents in the wheel limits
where the wheel will be positioned undermining the quadrature part of the
MGP wheel, so because of the detents, 100 pulses per revolution is probably the
There are two more wooden parts that need to be made. This is the plate that goes onto the bottom of the
box. Another nice feature about 2d contour is the option to mill both
situations like this. Hit the pause-resume, remove this piece which
the two socket head cap screws. The control box will press against that
plate and will clamp on to the stepper motor. A few of the wooden pieces are
screwed together in addition to being glued such as the clamp that goes around
the stepper motor. Horizontally this is a clearance fit while vertically as an
interference fit. We use four screws underneath to pull down this clamp
squeezing the stepper motor I know that doesn't sound like it would be very
strong but it is actually pretty rigid. I was going to use two cat6 cables but I
add ferrules to each conductor. I did wire up the differential return from the
MGP wheels but not all the connections require independent conductors. For
example, the push buttons just need to bring three inputs on the Pico systems
Universal stepper controller to ground so they share all the same ground as do
the MGP wheels. The emergency stop being, part of a series circuit, does require
two independent conductors. Technically, how the Pico systems board works one
side of the emergency stop push button could be ground and that could be the start of
your emergency stop circuit, but that's not how I did it. I think this is a neat
control panel and I haven't seen anything like this on another
I filter those slightly on LinuxCNC with a low pass filter to smooth out the
action. It's not perfect yet and it's going to require some additional work
but it's usable. Each detent is half of a thousandth currently and that gives me
plenty of resolution. It'd be nice to use this as an example for open source
controllers like LinuxCNC but realistically this setup could be done
on any controller with sufficient number of inputs and with a sufficiently high