scratch. And for me, where I'm at, and amount of time that I have available, I would
definitely buy another CNC conversion kit. Beyond saving a lot of time it gives
a chance to learn from an expert. Billy has decades of experience as a machinist
and for me to review how he has constructed his kit, after having done a
rudimentary 3d printed version of a conversion kit for this lathe, I learn a
lot. So, Billy got me going quickly, at a low cost, and with great quality
components that I get to learn from. The same is true the other two conversion
kits that I've owned [and installed]. The original industrial Hobbies conversion kit and
David Clement's PM25 conversion kit. As with any conversion there's a lot of
parts to remove. Here we're starting with the cross slide
leadscrew. Some parts have already been removed such as a longitudinal leadscrew
and the threading gear pivot bracket. With the cross slide slid back
we can see the Acme nut in the channel. Now I'll slide the cross slide off of
the saddle. The apron is held in place with a couple of screws. The half nut has
already been removed and that makes removal of the apron easier. To make room
for the ball screw we need to remove the Acme nut from the channel of the saddle.
As the saddle is removed from the bed it's likely that the saddle gib will
fall. We just have to be sure it goes back in the right spot. Here you can see
that saddle gib and that the Acme nut is held in place with a screw. Just
need to take the screw out and punch the Acme nut out. The saddle has tensioners
in the front and back and you want the saddle to move smoothly on the bed but
not be loose. If the saddle is loose it'll lift from the bed under a heavy cut and
pins and secured with screws. The first piece came off really easily
the longitudinal ball screw. The original tapered pins are driven through and used
to align the support. In all but a couple places on the conversion I was able to use
the original holes and screws. Billy has obviously gone to great lengths to
ensure this kit is easy to install. The only tools I needed were imperial and
metric hex wrenches. Before I install the longitudinal or the z-axis assembly I
thought you might like to see a few photographs of it.
The combination of pipe, plate, channel, and custom shapes is really clever. This
will save a lot of waste compared to milling everything from big hunks of
aluminum. Inscribing his company's name BD-Tools for Billy Dirk's Tools is a
nice touch and so is inscribing the Z and X axes names. They make sense when you
the cross slide or X-axis assembly. You may wonder why this assembly is so long.
There isn't enough room in the channel to mount any reasonable ballnut inside
of it and there isn't enough material in the saddle to mill a larger channel.
Also the cross slide is always going to come out over the apron, so while this
assembly takes up more space in the most forward position of the cross slide, it
takes up the same amount of space in the most aft position of the cross slide.
Or said another way, the space taken up by the cross slide assembly is constant
stepper motor drives prefer 36 volts but we can split the difference between 36
volts and 48 from this power supply by adjusting the power supply down to 42
parallel port breakout, it's like the cheapest one that Amazon sells but
it supports five axes, limit switches, and has a relay for a spindle control. You
find one that works with Linux reliably. I want to show you a little bit of the
and read the state of each of the input pins. Unfortunately we can't latch a pin
or hold a pin at a state and this particular breakout board uses pin 1 as
an e-stop out. We need to hold pin 1 high in order for the breakout board to come
out of e-stop. To create latching pins I'll change all of the buttons to check-buttons
by modifying the XML file. This is a little bit convoluted but it also
based systems so if you have different hardware you'll need to use a different
tool. This is the configuration for my system but it's really easy to assign a LinuxCNC
motor, pulley ratio, and leadscrew pitch. Travel distance is obviously important
jog each of the axes. With these small 157 ounce-inch
stepper motors, the Z-axis has a small amount of binding on the tail stock side.
One of the pieces of the apron is slightly rubbing the bed and a small
conversion kit there's gonna be small things like this that you have to solve but
the hundreds of hours that are saved make a conversion kit well worth it. This
is a simple pawn piece that I made in Fusion360. The LinuxCNC turn
post-processor isn't built into Fusion360 so I needed to download that. This is
the very first part that I cut after installing the conversion. There
were no rehearsals.
entire conversion process took less than a day. So unless you love the process of
designing a kit, consider buying one and use that time saved and your CNC