J-TECH Hobby-Fab OX Instructions Manual

OX Revised Build Instructions Rev 4.5 09/29/2018

1 | P a g e

Intro:

Thank you for purchasing the Hobby-Fab OX kit. The OX is widely popular and can be found around the globe. If you run across a
snag, feel free to send us a message or hop online; there are communities just for this machine. You can join the G+ OX
community (https://plus.google.com/communities/110852928951643236736) where you will find a helpful, experienced group
that uses this very machine.

The OX was first generated by Mark Carew. Our group soon picked up the design, cleaned it up slightly, and the end product is
what you are about to build. Good luck with this project and we look forward to seeing the awesome things you will create!

The below instructions will assist you in building the Hobby-Fab OX CNC kit. Each step begins with a BOM, then guides you
through that step. If something looks confusing, or a term doesn’t make sense, scroll a few photos up or down and the query will
most likely become clear.

Note:

The BOM has been double-checked by our team. We suggest a full inventory by the builder prior to beginning the build as well but
must warn, DO NOT open all boxes and dump all parts in a pile! This will make the build next to impossible to complete.

The extruded aluminum is cut to length. Pairs of the axis, i.e. both X gantry 20 x 60 and one 20 x 40 are cut together, surfaced
together, and bundled together to be an exact fit. The most frequent comment we get comes from builders unbundling the entire
kit and getting pieces and parts incorrectly assembled. We take extra precaution to ensure the kit goes together as smoothly as
possible. Leaving the extruded aluminum bundled up and parts in their step number box until you reach that step, will ensure a
smooth and quick build.

Shipping Damage – If there are any dents or dings in packaging please stop now and take pictures of the boxes. The most
damaged item in shipping is the aluminum extrusions. We will not replace damaged extrusions if the boxes are thrown away and
discarded prior to a notice being given about shipping damage.

Safety:

Use of a CNC can be dangerous. There is noise, electrical, respiratory, and other safety concerns. Please read about the use of a
CNC machine and understand its purpose and the materials you will be working with prior to continuing the build and use of this
machine.

Hobby-Fab, SMW3D, and its affiliates cannot bear any responsibility for damages or personal injury caused by the use of this
machine. It is up to the end user to ensure all safety matters are addressed and proper use of this machine is understood. Have
fun and be careful!

OX Revised Build Instructions Rev 4.5 09/29/2018

2 | P a g e

Step 1

Z-axis:

The M5 x 30mm bolts are pre-installed in the clamps.

600W upgrade:

The 600w spindle upgrade is mounted in the same fashion. The builder will also find the 600w power supply in step one.

OX Revised Build Instructions Rev 4.5 09/29/2018

3 | P a g e

Laser upgrade:

The spindle clamp with the M3 bolts installed will need to be the bottom clamp, see the end of this document for install.

Exploded View. M5 x 8 bolts go into Tee-nuts, M5 x 15 go into V-Slot.

Note here we are installing the black 90s on the inside, facing towards each other between the clamps, if this is difficult they can
be installed on the outside (top and bottom) of the clamps.

1. Slide the clamps over the spindle motor (these are a tight fit, you can open them with slight hand pressure to install over

spindle).

2. The clamps should ride at the top and bottom of the spindle, the bottom clamp should be approximately 40mm from the

bottom of V-Slot extruded aluminum.

3. Loosely install the M5 x 30 bolt in the spindle clamps and tighten at the last step. Perform on a flat surface so both clamps

are oriented the same direction.

4. Slide Tee-nuts in V-Slot

5. Install M5 x 8mm bolts through black 90 brackets into tee-nuts in V-Slot loosely.

6. Install spindle clamps to black 90 brackets with M5 x 15mm bolts.

7. Once all is aligned, tighten M5 x 8mm, M5 x 15mm, and M5 x 30mm bolts.

Now we install the threaded rod plates.

OX Revised Build Instructions Rev 4.5 09/29/2018

4 | P a g e

8. The smaller plate goes on the bottom, the bearing recesses (on the threaded rod plates) face each other. Install with 3 qty

(per side) self-tapping screws and leave loose. Note, we provide a screw driver, but the self-tapping screws are much
easier to set with a drill motor.

9. Now that the self-tapping screw threads have been set, you will need to remove either the top threaded plate or the

bottom threaded plate for step 3. It is easier to set the threads before we do the final assembly, hence doing it here then
removing them for the final assembly.

We are now completed with this step; the assembly can be set aside.

OX Revised Build Instructions Rev 4.5 09/29/2018

5 | P a g e

Bearing recess

OX Revised Build Instructions Rev 4.5 09/29/2018

6 | P a g e

Step 2:

X_Z-Axis gantry plate assembly:

Before we begin this step let us look at how to assemble a wheel assembly. Note the package comes with the bearings and shims
loose. You will need to build the wheel kits. See here:

Bearing, shim, wheel, bearing. In some instances, the additional shim is required outside the wheel, the extra shim is not used in
this build. Do not use both shims inside the wheel. If the additional shim is required, the build instructions will indicate where to
put them.

After you build at least 6 qty wheel kits it is time to continue the X_Z axis build.

OX Revised Build Instructions Rev 4.5 09/29/2018

7 | P a g e

The limit switch will face down. This is what will be considered the Z limit switch.

OX Revised Build Instructions Rev 4.5 09/29/2018

8 | P a g e

1. Begin by installing M5 x 20mm bolts in the center two holes, and the smaller holes as shown here:

*NOTE: We added a Z limit switch during the writing of these instructions. The gantry plate has since been modified in shape. The

sharper corners face towards the bottom of the Z axis. The limit switch should be installed on the side of the plate that the
bolt heads (not threads) are on. The images used will show the old profile of the plate in some instances, such as above.

OX Revised Build Instructions Rev 4.5 09/29/2018

9 | P a g e

2. Next install 2 qty M5 nuts into the plastic ACME nut block. Note one side has cut outs for the nuts.

OX Revised Build Instructions Rev 4.5 09/29/2018

10 | P a g e

3. Tighten the M5 x 20 bolts holding the black plastic ACME nut block on, snug, do not crush the plastic nut… it is possible!

The bolts need to be tight, not torqued.

4. Next install the spacer blocks (long black pieces) there are threaded holes that the M5x20 bolts will affix to as shown

above.

5. Afterwards slide the M5x45 bolts into the holes in the back of the plate, through the spacer blocks as seen here:

OX Revised Build Instructions Rev 4.5 09/29/2018

11 | P a g e

6. Now we will install eccentric spacers on one spacer block and plain spacers on the other. Next install the thinner spacers

(3mm) on top of the eccentric and standard spacers. The eccentrics (later) will allow for us to remove slack from the drive.
Before installing the eccentric spacers, note that one set of holes on the rear of the X gantry plate is larger than the other.
Install the eccentrics on the larger hole set:

OX Revised Build Instructions Rev 4.5 09/29/2018

12 | P a g e

7. Install the eccentrics with the cut-out (on the flange of the eccentric spacer) facing towards the outer edge of the plate.

8. Install the wheels and snug up the M5 nuts holding the wheels onto the M5 x 45mm bolts.

OX Revised Build Instructions Rev 4.5 09/29/2018

13 | P a g e

OX Revised Build Instructions Rev 4.5 09/29/2018

14 | P a g e

Step 3

Complete X_Z gantry assembly

In this step, we will build the X_Z gantry assembly.

1. Begin by installing the ACME rod in the ACME nut block from step 2. (NOTE) The ACME rod is in bottom of the

12”x12”x12” square box that all the parts came in.

OX Revised Build Instructions Rev 4.5 09/29/2018

15 | P a g e

2. Install a 688zz bearing and lock collar on each end. Reverse order shown below, lock collar goes on first.

3. Position the Z axis from step one (with one removed threaded rod plate) over the wheels and slide into place.

Be cautious of the tension between the wheels and the 20x80, if it is too tight make sure the eccentrics are properly
placed.

OX Revised Build Instructions Rev 4.5 09/29/2018

16 | P a g e

4. Next, with the screws loose on the threaded rod plate, we will align the bearings with the recesses in the threaded rod

plate.

5. Push the bearings into the recesses of the threaded rod plates, then tighten the threaded rod plates in place.

OX Revised Build Instructions Rev 4.5 09/29/2018

17 | P a g e

6. Once the threaded rod plates are tightened down, lock the bearings in place with the lock collars. NOTE: you will need to

leave about 2mm of ACME hanging out of the bottom of the lower (smaller) threaded rod plate. The above pictures shows
an exaggerated amount hanging out for display.

OX Revised Build Instructions Rev 4.5 09/29/2018

18 | P a g e

7. Check to make sure there is little to no play when you turn the ACME by hand. Also check to make sure the

ACME does not bind when turning by hand. If it does either adjust the lock collars or threaded rod plates to remedy this.

8. Next install the 6.35mm x 8mm coupler on the ACME rod. This goes on the top, the side with the larger threaded rod

plate. Slide the coupler down on the ACME till it stops and tighten the lower set screw on the lock collar.

OX Revised Build Instructions Rev 4.5 09/29/2018

19 | P a g e

9. Grab the NEMA 23 stepper motor install 3 qty M5 x 45mm bolts in any three holes, slide one each 20mm spacer and nine

mm spacer over each bolt.

OX Revised Build Instructions Rev 4.5 09/29/2018

20 | P a g e

10. Now slide the stepper motor shaft into the coupler and run the three bolts into the matching holes in the threaded rod

plate.

11. Follow this with installing three qty M5 nuts and tightening the coupler onto the motor shaft.

Note: The spacers 20 and 9mm may be exchanged for 3 qty 1.5” spacers.

OX Revised Build Instructions Rev 4.5 09/29/2018

21 | P a g e

Tighten the M5 nuts to secure the motor.

12. Recall the eccentric spacers installed on one of the spacer blocks above. It is now time to give these a turn and take the

side to side slack out of the Z axis. When installed we did so with the cutouts facing the outside of the plate, as seen here:

OX Revised Build Instructions Rev 4.5 09/29/2018

22 | P a g e

Taking the 8mm combination wrench turn each eccentric 1/8 of a revolution of a turn at a time. The wheels will get closer to the
20x60x180 extrusion. Do the top eccentric, middle, bottom. Physically feel the play in the wheel. If there is a lot of play, i.e. you
can turn the wheel freely do another 1/8 of a revolution turn. Repeat till all three wheels on the left side and right side of the
20x60x180 extrusion all slightly drag. DO NOT OVER-TIGHTEN, you can damage the wheel by tightening them too much. The
wheels should not lock on the metal, just rub.

The X_Z gantry is now complete.

OX Revised Build Instructions Rev 4.5 09/29/2018

23 | P a g e

Step 4

X gantry assembly

Note, again limit switches were added to the scope of the OX kit, some images below will not show the limit. The limit switch gets
installed on the side of the head of the bolts as shown here:

Revision update:

In May of 2018 Hobby-Fab/SMW3D made a change to the motors and made wiring easier. The builder will notice the barrier
blocks, motors, and limits in this step. The change removes the motor mounting hardware of M5 x 20s and M5 nuts as they are no
longer needed. Four quantity M5x10 are now used. This applies to step five as well.