MillRight M3 KIT Assembly Instructions Manual

ASSEMBLY INSTRUCTIONS FOR THE MILLRIGHT CNC MODEL M3 KIT

Version 1.11

Important safety rules for operating your MillRight CNC M3:
Never place your hands near a spinning end mill or bit.
Unplug the router before changing cutting tools.
Always wear eye and hearing protection while operating your machine.
Always run dust collection or wear a mask while performing a milling operation.
Do not leave the machine unattended while running a milling operation.
Do not operate your machine while under the influence of alcohol or drugs.
Do not place your hands between the bed and frame while the machine is moving.
Visually inspect wires prior to power up to prevent short circuits.
Ensure work pieces are properly secured before running a milling operation.
Always wear the red tinted safety glasses when operating the laser (if equipped).
Research material considerations prior to machining or lasing (if equipped).

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Welcome to the assembly instructions for the MillRight CNC Model M3 kit. Assembly will
take between eight hours and a weekend depending on your experience, tools, and work pace.
Don’t get in a rush. Although you are probably eager to get your machine together, it will pay
off to take your time and have fun along the way. We encourage you to read the instructions all
the way through first. This will help you understand how the step you are working on ties into
the next. After that, follow these instructions step by step. If you get stuck or just have general
feedback, please email us at [e-mail]. We strive to email back within a day.

Tools Required:

Phillips Screwdrivers, #3, #2, and #1 sizes
Small Adjustable Wrench
Needle nose pliers

8mm socket with socket driver (preferred) or ratchet and extension (acceptable)
10mm open end wrench

Allen wrench (also known as hex keys), sizes M1.5, M2, M3 (set screws and other
hardware socket sizes can vary)

Basic voltage meter (needed to set stepper driver current)
Hammer (needed to nail one wire retaining clip and tee nuts)
Note that these are just the minimum tools recommended to assemble the kit.

Items included in basic kit: (Materials in upgrades not listed below)
(1) Set of laser cut aluminum plates including (1) X Axis Bearing Plate, (1) Z Axis Bearing Plate, (2)

Y Axis Bearing Plates, (1) Y Belt Anchor Plate, (1) Z Spring Stud Bracket
(1) Precision cut MDF frame set including front, rear, left, and right pieces

(12) V wheel kits with each including (2) 625-2RS bearings, (1) Polycarbonate V Wheel, (1) M5

Screw or M5 Bolt, (1) M5 washer, (1) M5 Nylock nut.
(6) Fixed aluminum spacers, ¼’’ (6.35mm) long (In bag with V Wheels)
(6) Eccentric spacers, ¼’’ (6.35mm) long (In bag with V Wheels)

(1)

24 Volt Power Supply, adapter to break out barrel plug to individual wires, small length of wire

for connection from power supply adapter to CNC shield

International buyers must supply their own plug

(3) NEMA 17 Stepper Motors
(2) NEMA 17 Steel L Bracket Mounts (you only need two, the Z motor mounts to the X plate)
(1) Generic Uno (electronic controller board)
(1) Generic CNC Shield with (4) DRV8825 Stepper Motor Drivers (one extra)
(1) Fan for cooling the Stepper Motor Drivers (always point it close to the drivers!)
(2) V Slot Rails 2020
(1) V Slot Rail 2040
(1) MDF bed with (16) pronged tee nuts with #10-32 threads (nuts in hardware kit)

(10) 90 degree cast aluminum corner brackets. NOTE: Beginning in January 2017, some kits started

shipping with slots in the frame to allow for clearance of the tabs on the corner brackets. If your

kit is like this, then (8) corner brackets will still have all tabs and (2) will have the tabs ground

down on one side. The two with tabs ground down are for mounting the idler bearings

(10) 625-2RS bearings (In bag with corner brackets; for X, Y, Z idlers, not related to V wheels)
(4) Linear rod mounts

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(2) Chromed, hardened linear rods, 8mm diameter
(4) Linear bearing blocks for 8mm rod
(3) Pulleys, GT2 profile, wide (In bag with hardware)
(3.14) Meters of GT2 belt, 9mm wide [ (1) 900mm, (1) 1200mm, (1) 1040mm section ]

(3) Aluminum spacers, 10 mm long, 8mm OD, 5.1mm ID (for spacing of Z pulleys) (In bag with

hardware)
(1) Extension spring (In bag with hardware)
(1) Hardware set (See the resources section of www.millrightcnc.com for a hardware matrix)

The contents of each order are independently checked by two people to confirm that everything is
included. If you find you are missing something, contact us at [e-mail]

Overview of build steps:
V Wheel Kit Assembly
Y Axis Stage Assembly
Z Axis Bearing Plate Assembly
X Axis Stage Assembly
X & Z Axis Assembly Connection to Y Axis Assembly
X & Y Axis Motor Mounting and Belt Routing
Homing Switch Installation (only if you ordered this upgrade)
Rigidity Kit Installation (only if you ordered this upgrade)
Controller Mounting and Software Configuration
Stepper Drivers, Stepper Connections, and Powering Up

V WHEEL KIT ASSEMBLY

Locate the (12) V Wheel Kits included with the basic kit. NOTE: Those that ordered the rigidity
kit upgrade should assembly the extra (2) V wheels that you have now. Take the wheel body and
snap (1) 625 bearing into one side. Run an M5 bolt through the inside hole of that same bearing,
then flip it over in your hand. Slide an M5 washer that comes in the V Wheel Kit down over the
threads of the M5 Bolt. This helps properly locate the washer on the race of the bearing. DO

NOT FORGET TO INSTALL THIS WASHER BETWEEN THE TWO BEARINGS, OR THE V WHEEL WILL NOT
SPIN WHEN TIGHTENED AND WILL BE VERY HARD TO GET BACK APART. While leaving the bolt in,
snap another 625 bearing into the wheel. It may take some effort as sometimes it’s a pretty tight
fit. Set the assembled V Wheel Kits to the side for use in the next steps.

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Y AXIS STAGE ASSEMBLY

Locate the Y Axis Bearing plates and (8) of the V wheels that you assembled in the last step.

Grab one of the V wheels and one of the Y Axis
Bearing Plates. Install an M5 bolt through one of
the holes indicated in the picture to the right.

Now install a non-adjustable 6.35mm (quarter inch) spacer on the opposite side of the plate,
sliding it over the threads of the bolt. Install an assembled V Wheel onto the threads of the bolt,
then tighten it down using an M5 nylock nut.
Using an Allen wrench or Phillips screwdriver

(depending on if your kit came with allen or phillips
head M5 screws) and 8mm socket, get these snug

now. Don’t torque too much, just a bit of tension is

fine. If you are straining as you tighten, it is FAR too
tight! The wheel should still turn fairly freely once
tightened. If it’s really hard to spin, back off the nut
a tad. Install another V wheel the same way in the
other hole indicated by the arrow.

Now, take an eccentric spacer and put it in one
of the holes opposite those installed that you just
installed. Spin the eccentric spacer in that hole
and observe how the bolt hole in the spacer gets
closer then farther away from the V wheel kits
that you already installed. This will allow you to
snug up the bearings to the V rail after installing

them. Leave the eccentric spacer in its loosest position (bolt hole farthest away from the other
bearings). Now run an M5 socket head bolt through the plate, then the spacer, then install a V
wheel and loosely install an M5 nylock nut. You should end up with the bolt head, then Y Axis
Bearing Plate, then eccentric spacer, the V wheel, then an M5 nylon nut. Do NOT tighten these
very much yet because you will need to be able to spin the spacer soon. Install another
eccentric spacer and V wheel in the other hole just like you did this one.

Repeat these steps to install the V wheels on the other Y Axis Bearing Plate. Keep the assembled
Y Axes Bearing Plates nearby.

Locate both 2020 V rails as well as the front frame piece (long rectangular piece with four holes in
the middle). Notice the small half circle notch at the bottom of this piece. If that notch is at the
bottom left, then you are looking at the front side of the piece. Check out the middle picture on
page 22 to see the correct orientation of this piece when installed.

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Using a flat surface, flip the front MDF frame part
upside down and slide an M5 washer on a self­drilling screw, then start threading the self­drilling screw into the appropriate hole of the
MDF frame. Once the head of the screw starts to
poke through the other side, slide the center hole
of the 2020 V rail over the screw point.

Press the V rail against the MDF frame, while
holding it down against the flat surface and keep
driving the screw in. Get it snug, but not super
tight. The machine is designed for the top of the
Y Axis V Rails to flush up to the top of the front
frame piece, so flipping it upside down and
using a flat surface will help flush things up.

You should now have both 2020 V Rails screwed
into the front frame piece. Grab one of the Y
Axis Bearing Plates that you already installed the
V wheel bearings on, and slide it onto the right
V rail. Notice that the Y Axis Bearing Plate has
one side that is longer than the other. The
longer side (the one with four total holes, two of
which have eccentric spacers in them), will go
towards the outside. The bolts on the outside
wheels should be loose enough to allow you to
spin the eccentric spacer with a 10mm wrench,

but not “sloppy loose.” Now spin the eccentric

spacer on one of the v wheels so as to tighten

the V wheel into the V channel in the V rail. It’s

probably already almost tight enough.

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Tighten both eccentric spacers an equal amount. These wheels will need very little tightening with
the spacer. TAKE VERY CAREFUL NOTE OF THE FOLLOWING, OR YOU WILL CAUSE YOURSELF A

PROBLEM LATER. DO NOT OVERTIGTHEN THE V WHEELS INTO THE V RAIL. THE V WHEELS ARE
MADE OF A VERY TOUGH PLASTIC (ACETAL OR POLYCARBONTE), BUT THEY WILL DEFORM IF
TIGTHENED TOO MUCH, LEAVING YOU WITH

CLUNKY MOTION WHICH WILL RESULT IN POOR
CUTS. SET THE TENSION SUCH THAT YOU CAN

DRIVE THE ENTIRE Y AXIS BEARING PLATE BY
ROLLING A WHEEL WITH YOUR FINGER BUT LOOSE
ENOUGH THAT THE WHEEL WILL SLIP IN THE RAIL
IF YOU LIGHTLY HOLD THE Y AXIS BEARING PLATE
WHILE YOU SPIN A WHEEL. Slide the bearing plate
back and forth to make sure that it glides
smoothly along the rail. If the wheels are too
tight, loosen the spacer a bit and recheck. Note
that, if over time, you find the wheels develop a
flat spot over time from being too tight, you can
loosen the wheel and it will move back to its
circular shape in a few hours.

Now find the back frame piece (the other long
rectangular piece). Slide the Y Axis Bearing Plates
that you just installed onto the rails all the way to
the Front Frame Piece. Hold the Back Frame Piece
upside down and cantilever the Front Frame Piece
and Y Axis Bearing Plates over the edge of your
table so the other side of the rail flushes up to the
Back Frame Piece. Slide an M5 washer onto a

self-drilling screw and place it in the appropriate hole. If it’s snug in that hole, continue to turn it
through the Back Frame Piece until the drill point of the screw is sticking out. Slide the tip of that
screw into the center tap how of the V Rail. Do the same with the other rail. Grab the rail firmly
with your hand as you tighten. The torque of threading the screw tends to cause the rail to spin,
which you want to prevent. As you start to get good bite into the V rail with both screws, you can
set this assembly in its natural position (as it will be on the completed machine) in order to make

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tightening and alignment easier. Remember that the top frame piece should flush up to the top
of the V rail. Make sure it ends up that way when you finish tightening the screws. Now confirm
that the rails are close to parallel. This shouldn’t be a problem, but the holes sometimes allow
for a bit of a free fit for the screws, so you will want to check this and adjust accordingly. If you
have a square, you can check that the rail and the frame pieces are perpendicular, but this
usually just arises naturally from how it all goes together. Flip them back over and sit it down on
a known flat surface. If there is a bit of rock back and forth, you need to slightly loosen one or
more of the self-drilling screws

Keep this close and find the MDF bed. Lay the bed top down so you can see all of the pockets
that look like this:

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Flip the bed back over so the Y Axis Assembly is upside
down. Using your hammer, tap the T-nuts into the 16
holes labelled “A” in the above diagram.

Now find the Y Axis Belt Anchor Plate. Slide an M6 washer onto an M6x25 screw then put the
bolt through the plate in the orientation shown below. If you were looking down at the plate
in this orientation, you should see the bolt heads. In this orientation, the M6 screw needs to
go through an M6 flat washer, through the plate, then through a split-lock washer, then

secured with an M6 nut. Get a final tighten on the nuts now. These don’t screw to anything

else, they just serve as studs to anchor the belt.

Put the Y Belt Anchor Plate against the bed so the heads of

the M6 bolts are laying inside the holes marked “D” in the

center of the above picture. Line up the holes on the
corners of the Y Belt Anchor Plate with the holes marked

“B” that form a square around the holes marked “D.” Slide
an M5 washer onto a 5/8” wood screw, then screw it into

the bed in order to secure the Anchor Plate to the bed. DO
NOT OVER-TORQUE THESE OR THE SCREW WILL RIP THE

HOLE OUT. Pick one corner to start, and leave the screw
a little loose. Line up the hole on the opposite corner,
then screw it in. Put a final torque on the four wood
screws once you have them all in. A contributor to this
kit’s development has suggested inserting the screw
fully, pulling it out, putting a couple drops of

superglue (not included) in the hole, and
immediately rethreading the screw in the
hole. This is intended to prevent the screws
from vibrating loose over time.

You will now install the Bed onto the Y Axis
Assembly. Orient the bed so that it holes are
facing up, like in the diagram above. The holes

designated as “C” above are recesses for the

bolt heads of the V Wheel Kit bolts that are
on the Y Axis Bearing plate. Flip the Y Axis

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Assembly upside down and
lay it onto the bed so that
these bolt heads lay in
those recesses. Looking at
the bed in the orientation
above, the Front Frame
Piece should be towards the
top. Notice that each Y Axis
Bearing Plate has three
small holes left. Line these
holes in the plate up with
the small pilot holes. Slide
an M5 washer onto the
wood screws, then begin to
thread it into the holes. Do
not tighten the wood
screws down until you get
all the screws in both
bearing plates (six total,
three in each plate). Check

as you tighten the screws
down that the bed flushes up
to the front of back Frame
Piece. It should not be
canted or twisted. After you

finish mounting the bed, flip
the Y axis assembly back
over and slide it back and
forth to ensure that the
motion is smooth. If not,
either the eccentric spacers
are too tight or the bearing
plates were a bit cocked
relative to one another

when you torqued them down tight.

Z AXIS BEARING PLATE ASSEMBLY

We will now assemble the Z Axis plate. This is the plate that will carry your router or spindle
up and down. The diagram to the below shows the FRONT of the Z Axis plate. Notice that the

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position of the holes marked (A) being
slightly left of center will help you orient
the plate properly. The Z Axis plate was
designed to accommodate some of the
most popular choices in hobby CNC.
Hopefully, you’ve already selected the
router/spindle and mount combination
that you wish to use. See

www.millrightcnc.com/FAQ for more info

on the compatible spindles and mounts if

you don’t already have one. We have also

included some dimensional information
about the mounting holes for those
interested in making their own mount or
confirming fitment of available mounts.

The hardware used in each hole is as
follows:

Each one of these will be installed such that the head of the
screw or bolt is visible as you view the Z Axis Bearing Plate in
this orientation.

A: M5x30 - Belt Idler
B: M4x10 – Bearing Block
C: M4x14 – Bearing Block / Spring Stud Bracket

We will first assemble the idler bearings on your Z Axis plate.
Each idler is made of two 625 bearings, so go ahead and grab
four 625 bearings, two M5x30 bolts, 4 M5 flat washers, two
10mm long aluminum spacers, and two M5 Nylock nuts.

TAKE NOTE THAT THE ALUMINUM SPACERS USED HERE ARE
LONGER THAN THE ALUMINUM SPACERS USED WITH THE
NON-ADJUSTABLE V WHEELS. Slide an M5 washer onto the
M5x30 bolt and put the bolt through one of the holes
labelled with (A) in the above diagram. You should insert the
bolt through the hole when looking at the Z Axis Plate as
shown in the diagram.

Be careful not to build things on the wrong side. Now, slide
the 10mm aluminum spacer on the bolt threads and butt it
up against the back side of the Z Axis Plate. Put on a 625

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bearing, followed by an M5 washer, and then

another 625 bearing. DON’T FORGET THE

WASHER BETWEEN THE TWO BEARINGS OR THEY
WON’T SPIN. Secure all of this with an M5 Nylock
nut. You want to get this good and snug, but

don’t go crazy. Looking down at the Z Axis plate in

the orientation shown in the diagram above, you
should have the head of the M5 bolt, an M5
washer, the Z Axis Plate, a 10mm aluminum
spacer, a 625 bearing, an M5 washer, another
625 bearing, and a Nylock nut. Install the other
idler this same exact was in the other hole
labelled with letter (A).

Now locate your linear bearing blocks. Notice in
the diagram that the top left of the Z Axis Bearing
Plate has two holes marked (B) and two marked

(C). The other three bearing blocks have all
(B) holes and use M4x10 screws with split­lock

washers. Install these bearing blocks on the Z Axis Bearing plate with M4x10 screws and M4
split-lock washers in the holes marked (B). You should see the heads of the screws when
looking at the Z Axis Bearing Plate in the orientation shown in the diagram above. The bearing
blocks should be on the back side of the plate.

The top left two holes are labelled (C) and will be used to mount the spring stud bracket. Use
M4x14 screws with a split-lock washer to mount the Spring Stud Bracket to the plate. You’ll
screw into the bearing block to secure this. Looking at the Z Axis Bearing Plate in the orientation
shown in the diagram, you should have the screw head, an M4 split-lock washer, the Spring
Stud Bracket, the Z Axis Bearing Plate, then the linear bearing block. Make sure you get the
orientation of this spring stud bracket correct. Slide an M6 flat washer onto the M6x50 screw
then put it in the slot in the Spring Stud Bracket with the screw threads pointing towards the
back of the Z Plate. Secure it with an M6 split-lock washer and an M6 nut. Slide one loop of the

extension spring onto the threads of the
M6x50 screw you just installed.
Sandwich the loop of the spring between
the M6 nut you already have installed
and another M6 nut so that the spring

naturally points to about the 10 o’clock

position. Looking at the Z axis plate in
the orientation shown above, you should
have the head of the M6 screw, a flat
washer, the Spring Stud Bracket, an M6

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