OX-Belt CNC Version 4.0 Mechanical Assembly Instructions





Safety Statement

The author of this document is not liable or responsible for any accidents, injuries, equipment damage, property damage, loss of money or loss of time resulting from improper use of electrical or mechanical or software products.

Assembling electrical and mechanical CNC machine components like power supplies, motors, drivers or other electrical and mechanical components involves dealing with high voltage AC (alternating current) or DC (direct current) and other hazardous items which can be extremely dangerous and needs high attention to detail, experience, knowledge of software, electricity, electro-mechanics and mechanics.

BEFORE MAKING ANY CONNECTIONS OR DISCONNECTIONS POWER MUST BE REMOVED FROM THE DEVICE AND THE CONTROLLER. FAILURE TO DO SO WILL VOID ANY AND ALL WARRANTIES.

Before starting please read though all the 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
  • Metal File
  • Screw Drivers
  • Builder‘s Square
  • While these instructions have drawings for the Large Ox, construction of the Small Ox is, in principle, the same.
  • 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.
  • 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’.
  • 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.
Item Description Quantity
1 Solid V Wheels 1
2 Ball Bearing 625 2RS 2
3 Precision Shim - 10X5X1 1

Click to expand

  • 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.
Item Description Quantity
1 OX Y Plate Right 1
2 5mm Nylon Insert Locknut 4
3 NEMA 23 Stepper Motor 1.26N.m (6.35 Shaft) 1
4 Metric Aluminum Spacers – 3mm 4
5 20mm M5 Low Profile Screws 4

Click to expand

  • 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.
  • Attach the timing pulley to the Motor shaft.
Item Description Quantity
1 OX Y Plate Right 1
2 OX Y Plate Internal 1
3 40mm M5 Low Profile Screws 7
4 Eccentric Spacer – 8mm Hex – 6mm 6
5 Precision Shim - 10X5X1 14
6 Solid V Wheel Assembly 7
7 5mm Nylon Insert Locknut 7
8 Metric Aluminum Spacers – 6mm 8
9 GT3 Aluminum Timing Pulley - 20 1

Click to expand

  • Complete both the left and right plates as shown below.

Click to expand

  • Attach the spacer blocks by lining up the spacer blocks with the bottom of the OX Z Flate Front, insert the 10mm screws into the smaller holes on the plate and the threaded holes in the spacer, The larger holes will line up with the between the spacers and the plate for the wheels in the next step.
Item Description Quantity
1 OX Z Plate Front 1
2 Plate Spacer 2
3 10mm M5 Low Profile Screws 4

Click to expand


  • 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.
Item Description Quantity
1 OX Z Plate Front 1
2 Eccentric Spacer – 8mm Hex – 6mm 3
3 Metric Aluminum Spacers – 6mm 3
4 Precision Shim - 10X5X1 6
5 Solid V Wheel Assembly 6
6 5mm Nylon Insert Locknut 6
7 Spacer Block (V-slot) 2
8 45mm M5 Low Profile Screws 6

Click to expand

  • Attach the nut block as shown.
Item Description Quantity
1 5mm Nylon Insert Locknut 2
2 8mm Acme Nut Block 1
3 20mm M5 Low Profile Screws 2

Click to expand

  • 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.
Item Description Quantity
1 OX Z Plate Back 1
2 5mm Nylon Insert Locknut 4
3 20mm M5 Low Profile Screws 4
4 NEMA 23 Stepper Motor 1.26N.m (6.35 Shaft) 1
5 Metric Aluminum Spacers – 3mm 4

Click to expand

  • 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.
Item Description Quantity
1 OX Z Plate Front 8
2 OX Z Plate Back 2
3 Eccentric Spacer – 8mm Hex – 6mm 1
4 Metric Aluminum Spacers – 6mm 4
5 Precision Shim - 10X5X1 8
6 Solid V Wheel Assembly 4
7 M5 Cap Head screws - 65mm 10
8 5mm Nylon Insert Locknut 2

Click to expand

Click to expand

  • 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).
Item Description Quantity
1 6.35 x 8mm Flexible Coupling 1
2 Metric Aluminum Spacer 40mm 3
3 55mm M5 Low Profile Screws 3
4 NEMA 23 Stepper Motor 1.26N.m (6.35 Shaft) 1
5 5mm Nylon Insert Locknut 3
6 Threaded Rod Plate - Nema23 1

Click to expand



  • Using 3 x 8mm screws, attach the Threaded Rod assembly to the Z-Axis V-Slot.
Item Description Quantity
1 8mm M5 Low Profile Screws 3
2 V-Slot 2060 280MM 1
3 Z-Axis Motor Assembly 1

Click to expand



  • Mount the X Gantry onto the Z-Axis V-Slot and, turning by hand, screw the Lead Screw into the Nut Block about half way.
  • Attach the Bearing, 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.
Item Description Quantity
1 X Gantry Assembly 1
2 300mm 8mm Metric Lead Screw / ACME 1
3 Z Axis Assembly 1
4 Ball Bearing 688Z 1
5 8mm Lock Collar 1

Click to expand



  • 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.
Item Description Quantity
1 8mm M5 Low Profile Screws 3
2 Threaded Rod Plate - Nema23 1
3 Ball Bearing 688Z 1
4 8mm Lock Collar 1

Click to expand


The completed X/Z assembly should look like this:

Click to expand

  • Test the assembly by hand turning the lead screw.
  • Adjust the 3 Eccentric Spacers with a 8mm 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.
  • Screw the 2060 and 2040 extrusions to the Y Plate using the below image as a guide for the placement.
  • Complete the next step before attaching the other X-Axis plate.
Item Description Quantity
1 V-Slot 2060 1000mm 2
2 OX Y Plate Right 1
3 15mm M5 Low Profile Screws 16
4 V-Slot 2040 1000mm 1

Click to expand

  • Slide in 2x T-Nuts into each of the outside 2060 extrusion, 2x into the middle extrusion of the inside 2060 and 2x on the lower grove on the inside of the 2040.
  • Slide the X/Z Gantry onto the 2060 extrusion.
Item Description Quantity
1 V-Slot 2060 1000MM 1
2 V-Slot 2040 1000MM 2
3 Tee Nut 10
4 X/Z Gantry Assembly 1

Click to expand



There are 2 kinds of angled corner brackets that you may be supplied with. There are 90 degree angled corner brackets and 90 degree cast corner brackets. Please see below for the differences between the two plates. The functionality is identical.



  • If you have the 10x Cast Corner Brackets, you will need to file back the tabs on 1 face of each of the brackets.
  • Attach the Cast Corner Brackets as shown below ensure the flat side of the bracket you just filed is flat against the OX plates.
  • If you have the 10x 90 degree Angle Corner Connector (V-Slot), you can just attach them normally as they have no tabs.
Item Description Quantity
1 5MM Nylon Insert Locknut 10
2 8MM M5 Low Profile Screws 10
3 Cast 90 Degree Corner Bracket / 90 degree Angle Corner Connector (V-Slot) 10
4 Tee Nut 10
5 15MM M5 Low Profile Screws 10

Click to expand

Click to expand

  • 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.

Click to expand

  • Here is a picture of how the Base assembly will look once you have completed the below steps.

Click to expand

  • 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.
Item Description Quantity
1 V-Slot 20 x 40mm 750/1000/1500mm 2
2 V-Slot 20 x 40mm 750/1000/1500mm 2
3 V-Slot 20 x 80mm 750/1000/1500mm 2
4 Universal L Brackets – Double- Black 8
5 8mm M5 Low Profile Screws 52
6 Tee Nut 44
7 5 Hole 90 Degree Joining Plate 4

Click to expand

  • A T-Nut and an 8mm screw function as a belt clamp. Prepare each end (6 in total) as per the drawings below:
Item Description Quantity
1 8MM M5 Low Profile Screws 2
2 Tee Nut 2

Click to expand



  • 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.
Item Description Quantity
1 GT3 Aluminum Timing Pulley – 20 1
2 GT3 Timing Belt – By the METER 3 - 6

Click to expand

Click to expand

Click to expand

Post Assembly Notes:

  • 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.

Bill of Materials for OX Version 4.0


Item Description SKU Quantity
1 Ball Bearing 688Z BEAR-688Z 2
2 GT3 Timing Belt – By the METER BELT-GT3-1M 3 - 6
3 GT3 Aluminum Timing Pulley – 20 BELT-GT3-TP20 3
4 Cast – 90 Degree Corner Bracket /90 degree Angle Corner Connector (V-Slot) BRAC-90CAST/BRAC-90ANG 10
5 Universal L Brackets – Double- Black BRAC-L2-B 8
6 300mm 8mm Metric Lead Screw / ACME HARD-ACME-8-300 1
7 8mm Acme Nut Block HARD-ACME-8-BLOCK 1
8 8mm Lock Collar HARD-COLL-8MM 2
9 6.35mm x 8mm Flexible Coupling HARD-COUP-635×8 1
10 V-Slot 20 x 40mm 500/750/1000/1500mm LR-2040-S-500/750/1000/1500 3
11 V-Slot 20 x 40mm 750/1000/1500mm LR-2040-S-708/960/1460 2
12 V-Slot 20 x 60mm 500/750/1000/1500mm LR-2060-S-500/750/1000/1500 2
13 V-Slot 20 x 60mm 280mm LR-2060-S-280 1
14 V-Slot 20 x 80mm 750/1000/1500mm LR-2080-S-748/1000/1500 2
15 5 Hole 90 Degree Joining Plate PLATE-90-5 4
16 Threaded Rod Plate – NEMA23 PLATE-ROD-NEMA23 2
17 Ox Plates (Version 4) PLATES-OX-SET 1
18 Spacer Block (V-Slot) PLATE-SPACER 2
19 Eccentric Spacers – 8mm Hex – 6mm Height SHIM-ECCENTRIC-8-6 19
20 Precision Shim – 10x5x1mm SHIM-PREC-1051 54
21 Metric Aluminum Spacers 3mm SHIM-SPAC-3MM 12
22 Metric Aluminum Spacers 6mm SHIM-SPAC-6MM 25
23 Metric Aluminum Spacer 40mm SHIM-SPAC-40MM 3
24 Solid V Wheel WHEEL-SOLIDV-KIT 28
25 Nylon Insert Locknut HARD-NUT-LOCK-5MM 31
26 Tee Nut HARD-TNUT 60
27 M5 Cap Head Screws – 65mm SCREWS-M5-CAP-65 4
28 8mm M5 Low Profile Screws SCREWS-M5-LP-8 74
29 10mm M5 Low Profile Screws SCREWS-M5-LP-10 4
30 15mm M5 Low Profile Screws SCREWS-M5-LP-15 26
31 20mm M5 Low Profile Screws SCREWS-M5-LP-20 14
32 40mm M5 Low Profile Screws SCREWS-M5-LP-40 14
33 45mm M5 Low Profile Screws SCREWS-M5-LP-45 6
34 55mm M5 Low Profile Screws SCREWS-M5-LP-55 3
  • manuals/ox_version_4.0_cnc_mechanical_assembly_instructions.txt
  • Last modified: 2022/11/04 02:10
  • by Maker Hardware Team