70 SERVO 05.2014
Imported Conversion Option
If you search eBay for MF70 conversion, you will
find a kit available from Turkey. The Y axis is shown in
Figure 6. While this kit does not require modification
of the mill, we won't be using it for the following
• There were issues with the fit and finish on this
unit. A rotary tool was needed to clean up
some of the parts.
• Some of the parts did not have the holes
tapped. I had to tap them myself.
• Ideally, a kit should be available locally.
• Very sparse instructions.
Even though we’re not using this kit, I can
honestly say that once it was installed it did work very
well. Kit cost is about $73. Again, if you go this route,
you will still have to purchase the support components
KRCNC Conversion Parts
When I decided that I was going to write an
MF70 CNC conversion book, it was important that the
components I chose were going to be available for a
long time. While controllers and steppers could be
swapped out as needed, the actual conversion kit
must remain a constant. In order for this to happen,
I needed to design my own. I came up with the
following requirements when designing the kit:
• The mounts must be able to be cut with a laser
as this is the fastest way to create parts quickly.
• The stock used for the mounts must be readily
• The stock must be paintable.
• The hardware used with the mounts must be
• The design needs to be flexible enough to work
with the existing knobs on the mill.
Figure 7 shows the Y axis for the design I came
up with. The stock is made from multiple layers of
baltic birch hobby ply. I have found this material to be
very easy to laser cut, yet strong enough to make a
very good mounting interface. It takes paint very well
and if covered with acrylic paint, becomes water
The layered approach has enough rigidity to hold
the motors and provide accurate power transfer, yet it
has enough flexibility to allow for clamping onto hand
wheels that are not perfectly round.
The laser cut parts (Figure 8) are available as a kit
from the krcnc.com website for $45. Please note that
these are meant to be used with this magazine article
(and my book) and do not include instructions.