OX CNC Version 3.0 Mechanical Assembly Instructions

The mechanical kit is based on the Open Builds Ox CNC Router designed by Mark Carew and published on openbuilds.com. There are however a couple of difference between Mark’s design and the Maker Store Ox Kit. None of the differences are that great and the Openbuilds YouTube videos available on putting the Ox together are a great resource and starting point for everyone. Most of the differences are a result of customer feedback and modifications published on a wide number of internet forums.

Please note that while we have spent a considerable amount of time and effort putting these instructions together, any errors and omissions excepted (E&OE). If you find an error, please let us know so we can continually improve this resource.

Before starting any build, it is always a great idea to get organised. Start by unpacking your kit and checking it against the BOM (Bill of Materials) in Appendix 1. If you find any parts missing, please contact Maker Store as soon as possible.

You will also need the following tools:

• 3mm Allen Key
• 8mm Spanner
• 10mm Spanner
• Screw Drivers
• M5 Tap
• Hack Saw (or other means to cut V-Slot)
• Builder‘s Square

1. While these instructions have drawings for the Large Ox, construction of the Small Ox is, in principle, the same.
2. It is Important to make sure all angles are square. As you progress through your build, use the Square to make sure everything is aligned before the final tightening of all screws and nuts.
3. This build requires some of the V-Slot to be tapped with a M5 tap. In general tap to a depth of 8-10mm. and clean away any swarf and burs.
4. When placing any V-Wheels onto the V-Slot, make sure the Eccentric Spacers are adjusted to their furthest point. Do not force the wheels on as this may damage them creating a little ‘bump’.
5. The Sketchup model is available for download from the Maker Store website. It is a fantastic resource and can allow you to move through the design, pull things apart, and measure wherever required. We strongly recommend downloading the model and becoming familiar with Sketchup.

Assemble all the Solid V Wheels as per the drawing. It can help to use one of the longer screws to align everything by threading the parts on one by one.

The NEMA23 stepper motor is attach as shown. Make sure the 3mm spacers are between the Gantry Plate and the Stepper. Don’t tighten too much just yet as a little play is needed when tightening the belts later.

Attach the wheels to the gantry. Use Eccentric spacers on the 3 lower wheel and 6.35mm spacer on the upper 4 wheels. Tighten the top sets but not the bottom as they will need to be adjusted when put on the V-Slot.

Complete both the left and right plates as shown below.

Attach the spacer blocks with M5 x 10mm screws. If you have 2040 for your Z-axis then use the nearer set of holes, if you have 2060 then use the otter set.

Using M5 x 45mm screws attach the V-Wheels through the Gantry Plate and the spacer blocks. Use 3 x Eccentric spacers on one spacers block and 3 x 6.35mm spacers on the other.

Attach the nut block as shown.

Attach the NEMA23 stepper to the gantry plate with 4 x M5 20mm screws, making sure to place the 3mm spacer in between the gantry plate and the NEMA23.

Placing the spacers, shims and wheels as per the drawings below, attach the front and back plates using the 4 x M5 x 65mm screws. Note two eccentrics are on each lower screw.

First make sure you have tapped (M5) all the holes in the Z-Axis V-Slot to a depth of approx. 8mm.

Attach Flexible Coupling to the NEMA23, then using the 40mm Spacers attach the NEMA23 to the Threaded Rod Plate as shown. Make sure the bearing recess in the plate is facing away from the NEMA23 (see below).

Using 3 x 8mm screws, attach the Threaded Rod assembly to the Z-Axis V-Slot.

Mount the X Gantry onto the Z-Axis V-Slot and, turning by hand, screw the Lead Screw into the Nut Block about ½ way. Attach the bearing and collar and push the Lead Screw into the Flexible Coupling. Tighten the coupling, make sure the bearing is correctly seated in the Threaded Road Plate recess. Slide the collar to the bearing and tighten.

At the other end, slide on the Lock Collar and bearing. Screw the remaining Threaded Rod Plate into the V-Slot. Seat the bearing and tighten the collar.

The completed X/Z assembly should look like this:

Test the assembly by hand turning the lead screw. Adjust the 3 Eccentric Spacers with a 10mm spanner to that there is no lateral movement. Tighten all screws and test again by hand turning the lead screw. If the gantry is to tight then re-adjust the eccentric spacers.

Before starting the X Axis Gantry, make sure to tap (M5) all the holes on the 2060 and 2040 to 8mm depth.

Screw the 2060 and 2040 to the Y Plate.

Slide in the T-Nuts and X/Z Gantry and screw the Y Plate to the 2060 and 2040.

Attach the Cast Corner Brackets as shown below.

Tighten the 4 Eccentric Spacers on the X/Z so that there is no lateral movement but the gantry can still move freely back and forth.

The completed X Gantry should look like this.

The 2 2040 x 1500mm lengths of V-Slot need to be cut to 1460mm to fit inside the frame. Before starting tap (M5) the 2080 ends to a depth of 8mm. Then put the base together as per the drawings below. Don’t forget to put the X-Gantry on before securing the last end! Also, make sure to tighten the Eccentric Spacers on each side.

If you haven’t already done so, put the GT3 Timing Pulleys on the 3 stepper motor shafts. Centre the pulley over the groove in the V-Slot.

A T-Nut and an 8mm screw function as a belt clamp. Prepare each end (6 in total) as per the drawings below:

Making sure the teeth are facing down, attach one end of the Timing Belt with the clamp and feed the rest under the V-Wheels, over the Timing Pulley, and under the V-Wheels. Pull tight and secure with the other clamp.

• Again, square your machine – for the X, Y and Z axis.
• Using T-nuts, a base board can be attached to the base. This will strengthen the frame and create a work surface.

Special thanks to:

• Mark Carew, Openbuilds and the Openbuilds forums
• The Open Hardware community
• Our fantastic customers, whose feedback constantly helps us improve our parts and the design of this great machine.