Hobby-Fab R7 Build Instructions

Last updated: 08/13/20108 Rev. 9

1

R7 Build Instructions

1. INTRODUCTION

The R7 is so named as this was the revision the SMW3D/ Hobby-Fab team released; this DIY CNC router
kit. The kit is fully open source. In addition, the kit was released in beta and all feedback taken to
improve build and functionality. Thank you for joining us on this journey. We truly hope this build will
help makers to achieve the satisfaction of creating a machine that will provide years of creativity with
their own two hands.

2. SET-UP

We would love for you to rip open this package like it’s Christmas morning and you are eight years old
again. We must warn though, we have individually bagged the steps and they will match the below
inventory as well as the videos on YouTube on the SMW3D/Hobby-Fab page. The videos are labeled
R7v1, this means R7 video one, etc. Please DO NOT open every bag and dump the build on the table.
This will severely impact your build time and locating the proper parts for the steps. The build videos are
very outdated, they should only be used for reference.

We also advise finding a large, clean, flat surface to build your kit. The first few steps can certainly be
performed on a smaller surface however, as the build grows, you will need a four foot by four-foot area
flat surface. It is also advised that you lay out each step individually with all parts for the respective step.
Lastly, before starting the build, please note the BOM (Bill of Materials) is described below and two
columns are present after the item description. Please open each bag prior to build and count each item
and check it off the below list. If anything is missing, please contact us at [e-mail].
Performing this task now will prevent having to put off your build in the event we missed something.

Finally, please have fun and take your time. The build process will control all your cuts after, build it
once and build it right. The machine will provide years of great service.

Tools Required: (all should be locally available) Additional Items Required

Metric allen wrench set Bucket for water

Soldering iron and solder Table

Metric tap set Computer

8mm combination wrench USB A to B cable

10mm combination wrench Square and level

Last updated: 08/13/20108 Rev. 9

2

Hand file

3. Build and BOM

The steps shown here will correspond with the SMW3D build videos. It should be noted these videos are
quickly getting outdated due to amazing feedback from users.

NOTE: as of November 2017, the mini wheels running inside the beam may be changed to Delrin.

NOTE: as of November 2017, mechanical limits are included in all R7 kits. The limits get installed as such:

Y gantry plate – limit faces rear of machine

X gantry plate – limit faces the right-hand side of the build looking at the machine

Z gantry plate – limit faces down

All wired NO

Step One:

In the first step, you will be assembling the Y gantry plates. These plates will run on the side of the R7 as
you are facing the machine. One notable change from the videos is the .2mm shims are no longer
needed. At the end of this step you will have two assembled Y gantry plates, each with eight mini wheels
and three large wheels (all on M5 x25 bolts), the ACME block will also be installed (M5 x 20 bolts). Take
your time on the wheels. If all wheels touch the C-Beam, you are in a great spot. We state in the video a
tension is required. We have found this is not true. Each plate can take up to an hour and a half to
completely assemble. So, sit back, relax, and let's build.

Last updated: 08/13/20108 Rev. 9

3

STEP 1

Qty.

Smw3D

Builder

Y Gantry Plate LH

1

Y Gantry Plate RH

1

Large Xtreme Wheels

6

Mini Delrin Wheels

16

Adjustable Tension Anti-Backlash Nut

2

6mm Spacers

8

6mm Mini Eccentric Spacers

14

3mm Spacers

4

M5x20 Bolt

4

M5x25 Bolt

22

Last updated: 08/13/20108 Rev. 9

4

Note, the large wheels get a shim from the wheel bag between the bearings but not between the
eccentric spacer and bearing. The mini wheels get a shim from the wheel kit, between the bearings in
the wheel and between the bearing and eccentric spacer. All bolts are M5x25mm bolts. Note, you will
most likely need to remove the limit switch to install the one wheel bolt that resides behind it.

Begin by installing the standard spacers on the smaller holes (bottom row), these will be a reference for
the rest of the wheels. Tighten these with a small amount of torque, do not tighten so much that the
wheel drags or locks. Next, install the next row up eccentric spacers and mini-wheels. Before tightening,
turn the eccentrics until the wheel on this bolt is as close to the reference wheel below it. Install and
correctly tension the inner mini-wheels on the inside of the C-Beam (250 length), before installing the
outer larger wheels. Install the large wheels on the eccentrics and adjust to the beam in the same
fashion.

Last updated: 08/13/20108 Rev. 9

5

The ACME block is installed by using two M5 x 20mm bolts, 3mm spacers, and two M5 nuts. Do not
over-tighten these M5 x 20 bolts, it is possible to collapse the block. Simply snug up and use lock-tight.

You can adjust the tension on the ACME block at this time if you so choose. Insert one of the ACME
threaded rods into the block and adjust the set screw until there is slight resistance while trying to turn
the ACME rod through the block. Do not overdo it. You can always adjust this after the build is complete.

Last updated: 08/13/20108 Rev. 9

6

Limit switch and barrier block shown installed.

Last updated: 08/13/20108 Rev. 9

7

Step 2:

Step two has us assembling the front X/Z gantry plate. While looking at the completed machine, this will
be the front plate that holds the Z gantry and moves side to side in the X direction. Recall front to back is
Y and up and down is Z.

Note a change from the video, the Z is now driven by a single adjustable tension acme nut. Set the
tension on the ACME as we did in step one. Insert the acme rod and turn in on the set screw until there
is a slight resistance to turning the rod by hand. Do not lock the ACME in place by adjusting too far.

STEP 2

Qty.

Smw3D

Builder

Front XZ Gantry Plate (Machined)

1

Large Xtreme Wheels

8

Mini Delrin Wheels

8

Adjustable Tension Anti-Backlash Nut

1

1/4" Spacers

4

1/4" Mini Eccentric spacers

12

3mm Spacers

2

M5x20

2

M5x25

16

Note that all wheels are installed with ¼” eccentric spacers in this step to allow adequate room for the Z
gantry.

To begin assembly, note that one side of the plate has recesses. We will be installing bolts from this side
and the eccentric and regular spacers on the other side. Also, you will note one side of the inner gantry
wheel holes is smaller in diameter, we call these the reference holes. Install these and tighten down the
wheels, then use the eccentrics to add tension to the opposite wheels. All wheels on the reference holes
should touch the beam, this ensures a true Z. Install and correctly tension the inner mini-wheels on the
inside of the C-Beam (250 length), before installing the outer larger wheels. Install the eccentrics so that
the wheels are as close as possible to the reference wheels. Install the beam and turn the eccentric until
the wheel touches. Start in the center and work toward the top and bottom wheels.

Last updated: 08/13/20108 Rev. 9

8

Install the outer wheels and turn the eccentrics until the outer wheels touch the C-beam.

The ACME block is installed in the same fashion as the first step.

Last updated: 08/13/20108 Rev. 9

9

Note limit switch on bottom of plate, these wires will remain loose till install.

Last updated: 08/13/20108 Rev. 9

10

Step 3:

Step three will be the assembly of the rear X gantry plate. The same principles apply here. Use the
reference wheels as a base and adjust the eccentrics to touch the inside of the sample beam (250mm
length Z). Continue by installing the ACME block with the supplied 3mm spacers and M5 x 20mm bolts.
Again, it is a good idea to adjust the tension on the ACME block at this time.

Note this plate is completely remodeled but the assembly remains the same.

Last updated: 08/13/20108 Rev. 9

11

Notch in plate faces down. Limit switch on the left-hand side looking at the plate.

Last updated: 08/13/20108 Rev. 9

12

STEP 3

Qty.

Smw3D

Builder

Rear XZ Gantry Plate

1

Adjustable Tension Anti-Backlash Nut

1

Mini Delrin Wheels

8

3mm spacers

2

m5x20

2

m5x25

8

6mm Spacers

4

6mm mini eccentric spacers

4

Last updated: 08/13/20108 Rev. 9

13

Step 4:

Step four will be the joining of the front to the rear X gantry plates. When you have all the large wheels
in place, apply a light amount of tension on the M5 nuts to hold everything together. Then, adjust the
eccentrics so that the wheels are as far away from the center of the X axis as possible.

Once the wheels are installed and eccentrics have them spaced out, slide your 250mm length C-beam in

and adjust the tension evenly. Turn ⅛ of a revolution on the two eccentrics on one axle at a time. Start

with the far-left top corner then go to the top right corner, then the right bottom, then the left bottom.
If all are touching, you’re done. If not, repeat by turning each axle eccentrics ⅛ of a rev again. Once the
outside wheels all touch, move to the inner wheels.

There are no shims used here except for those between the bearings on the wheel kit. The assembly is
plate, eccentric, wheel, 9mm spacer, wheel, eccentric, plate.

Last updated: 08/13/20108 Rev. 9

14

STEP 4

Qty.

Smw3d

Builder

Large Xtreme Wheels

16

9mm Spacers

8

6mm Mini Eccentric Spacers

16

M5x60

8

Last updated: 08/13/20108 Rev. 9

15

Step 5:

Step five we will mount the spindle to the Z gantry. The Z gantry will be the up and down axis of the
machine. Note, the spindle clamp has been modified from the video. These spindle clamps are very
fragile in the un-mounted state. Be cautious with these. Do not try to bend them or force them open
with excessive force. Simply slide the clamp on the end of the C-Beam, install with a T-nut and M5 x 8
screw on both sides, and tighten. The clamp will be tight when installing the spindle. You can gently
spread the clamp by hand and slide in the spindle. The clamps should be on the stainless caps of the
spindle.

STEP 5

Qty.

Smw3d

Builder

800w Spindle

1

Spindle Clamps

2

M5 T-Nuts

4

M5x8

4

M5x35

2

250mm C-Beam

1