Ronald L's CNC Machine Kit Build
is exhibited for the exceptional wiring work he has done and for a particular challenge
he needed to overcome. First, a word about the challenge. Ronald's motors that he
purchased contained shafts in a metric size and currently, my collars for the drive
sprockets are sized for imperial shafts of 1/4" diameter. His shafts were a little
too large and, upon my recommendation, he bored a larger hole. Unfortunately, the
bore did not center properly and he is faced with a need to purchase collars for
the motors shafts locally. When he overcomes this challenge, I will add more information.
The wiring work that he provided is truly exceptional. He even adapted PVC as conduit
on the z-axis.
His words follow:
The torsion box was made with one difference to save time, the top of the box is
in fact the table top. Put underneath some space for keeping MDF 4x2” sheets.
The angles on the rails were installed by using one of the bolts of the table. I
used a grinder to reduce the material for the angle to fit nicely inside the bottom
side of the rail I wanted to achieve one point in which the electrical cables from
the machine were connected somehow from the gantry to the table. I thought about
doing it on the air with some strings, but that was too much hassle. And the longer
the cables, the longer the loss (although my drivers are very easy adjustable with
a pot). The motors wiring on each of the gantry sides follow always the same connection
pattern for ease of use.
All of the motors’ cables have pin crimp terminals that are used in conjunction
with normal electrical block terminals for ease of use. These are screwed to the
MDF of the machine, anywhere I found it best for avoiding issues. And especially
for testing voltage, current, etc.. dead easy to do right on the motor and not on
the other end where the motor drivers reside. My driver enclosure (including the
power supply) is always closed on the floor and I never touch it in fact.
The cable used for the actual wiring as I’m using now bipolar drivers (BTW I just
recommend to anyone on your site NOT to use unipolar ones, they are really really
crap, these ones I’m using from Ocean Controls dudes are FAN-TAS-TIC for the price,
they barely get hot (no resistor or similar) and the motors get just normal warm,
whereas before they were working really hot) is 4 core normal white electrical PVC
cable rated at 6A as the 3A one was out of stock, would have used the 3A one though.
The 6A is a bit thicker, but works just fine and in fact better as there is less
For the Z axis cable-canal in inverted U shape I’ve done something really simple.
Went down to the local (fairly big) hardware store and got myself, 25mm electrical
PVC tube, a couple of PVC inspection bends, I glued them together and installed
them on right on the Z axis (4 screws) and they hang down to the back for perfect
usage. What I have not fixed yet is to avoid the cables to band too much, I take
it with much use the part where these are fixed to the block terminals might give
up, but for now it works like a treat. Through the conduit I’m running the spindle
power and the Z and Y axis motor 4-core cable. And that was it, dead easy. It takes
some time to plan, but once done is done! Note: When installing the inverted U shape,
sink down the Z axis to its lowest point, then fix the inverted U shape and leave
1” or 2” space between the chain and the tube, and viola! I’ve fastened the 3 cables
together to minimize any issues. I thought at first to use some flexible conduit
for this bit, but honestly this works as good.
For the other side of the gantry (the right side on the pictures) where you see
the 3 grey flexible conduits going down, I have used the base of the side of the
gantry to install a simple L shape aluminium angle in which I’ve fastened 3 straight
plastic swivel glands. These serve to attach the 3 flexible conduits (20mm ones)
in which I run 2 (motors) + 2 (motors) + 1 (router + limit switch -telephone type-
cable). On the other end down in the middle of the table, I’ve simply attached the
glands straight to the wood (3 screws per gland) and it’s really strong, so no issues
when the table moves fast. There is a picture with the table all the way down to
X0 and also another one on the other end. I’ve used cable fasteners to have all
3 conduits together to have it more tidy. This thing really works well and that’s
about it, I’m done with cables, don’t have to touch these any more for as long as
the table lives as it stands.