Heavy Mill Build Part-1

Thank you for purchasing a 3DTek.xyz Heavy Mill.

Please allow for several solid days in build and tune to get the Heavy Mill ready for use. Don’t rush – try to enjoy the build process.

Having an online guide will enable the use of videos and easily updated content.  If there is any part of this build you think needs more documentation attention or clarification – please email [email protected] or place a comment in the new Heavy Mill area of the discussion forum.


  • Please note – this is not an appliance – it is an industrial tool.
  • The construction and use of this machine pose many hazards to your safety.
  • This is not a tool to be left running unintended, as you would not leave any other power tool operating in your absence.
  • As for all power tools, Lose clothing/hair etc should be secured before approaching the machine.
  • Get used to wearing glasses when in the vicinity of this machine. Milling bits and other debris do get thrown from the machine.


The VFD, and power supplies pose a significant risk to your safety.

  • A licensed electrician should commission these items.
  • These items should be enclosed in a grounded or otherwise appropriate enclosure and kept clean of dust and moisture.
  • The machine should be installed on a circuit that is protected by an RCD and breaker

VFD (Variable Frequency Drive) also Known as VSD (Variable Speed Drive) varies the frequency of the output from the 50hz its supplied to within the range of 0-400HZ in order to manage the speed of the spindle.

This device has large capacitors, which can hold a charge for quite some time. Your electrician must commission this and the other power supplies on your behalf.

Kit Contents

Contents of the kits vary depending on the options selected at the time of purchase.

The base kit consists of:

Anodized Plates:


Plate PartsDescriptionQTY
SCPSpindle Carriage1
XHP_TopX Horizontal Top1
XVP_FrontX Carriage Plate Vertical Front1
XVP_BackX Carriage Plate Vertical Back1
XHP_BotX Horizontal Bottom1
XHP_MidX Horizontal Mid1
XMPX Motor Plate1
YMPY Motor Plate2
XPPX Pulley Plate1
YPPY Pulley Plate2
BCTBelt Clamp Top3
BCBBelt Clamp Bottom3
YCPY Carriage Plate Left1
YCPY Carriage Plate Right1
YCPZ Motor Mount1

Aluminium Extrusions:



PartDescription1000mm Qty1500mm Qty
4040 Rail4040 Rail – Base Structure46
X-Axis Rail8080 –  Tapped Both Ends M8 * 15mm11
Y-Axis Rails40120 –  Tapped Both Ends M8 * 15mm + Drilled & Counterbored holes.22
XDGRailX-Axis Drag Chain Support Rail 2040 T Slot11
YDGRailY-Axis Drag Chain Support Rail 2040 T-slot11

If you chose the T-Slot bed option, the following extrusions will also be included


PartDescription1000mm Qty1500mm Qty
Bed T-slot15180 – T-slot Bed Extrusion – If bed option is taken35
Bed T-slot Left Side15180 –  4-6 holes – if bed option taken11
Bed T-slot Righ Side15180 –  4-6 holes – if bed option taken11
T-Slot Tee ExtrusionT-Slot Connectors – if bed option taken46
Water Block Strip
12×3 MM Alloy Flat Bar strip – if bed option taken


Linear Motion

PartDescription1000mm Qty1500mm Qty
HGW20HGW20CC Linear Bearing Blocks66
HG20Linear Rail – ~990 / ~1490 mm22
HG20Linear Rail – ~1100 / ~1490 mm22

PartDescription1000mm Qty1500mm Qty
HSS16mm hardened Steel Shaft 225mm22
PBPillow Bearing Blocks SC16LUU22



Part/PurposeLabel CodeQty
Securing Z Pully on Acme ThreadM8 Flanged Nut1
8MM Steel Spacer sits below pulley on Z Acme8 mm Spacer1
Idler Pulley Spacer 5mm Bore (one inside, one outside Idler)3 mm Spacer6
Z-Axis Lead NutLead Nut1
X & Y Limit switchesM3 Nylock Nut8
X & Y Limit switchesM3 Washer8
Shaft Grubs ScrewsM3x10 BHCS4
Z Limit SwitchM3x16 SHCS2
X & Y Limit switchesM3x25 SHCS8
Drag Chain to Drag Chain Support ExtrusionM4 Tee Nut4
Drag Chain to Drag Chain Support ExtrusionM4x10-12 SFHCS4
Drag Chain MountsM5x12 BHCS4
Belt Clamp TopM4x25 SHCS6
Stepper MotorsM5 Nylock Nut24
Stepper MotorsM5 Star Washer16
Stepper MotorsM5 Washer16
Y Stepper MotorsM5x25 SHCS8
Z Motor MountingM5x16 BHCS12
Securing Bearing Rail, X Stepper MotorM5x20 SHCS104
Bolting together all other plate hardwareM5x20 FSHCS28
Motor Plates, Pulley PlatesM5x20 FSHCS18
Belt Clamp BottomM5x25 BHCS6
Idler Pulley AxelsM5x30 BHCS3
Y-Axis Limit Switch TriggersM5x40 BHCS2
X-Axis Limit Switch TriggersM5x70 SHCS2
Bearings In Y-AxisM6 Spring Washer16
Bearings In Y-AxisM6 Star Washer16
Bearings In Y-AxisM6x20 SHCS20
Bearings In X-Axis PlatesM6x20 FSHCS8
Securing WasteboardM6 Tee Nut30
Spindle Clamp BoltsM6x50 SHCS4
Y Plates to X-Axis Extrusion / End Plates to Y Extrusion, Spindle MountM8 Spring Washer24
Y Plates to X-Axis Extrusion / End Plates to Y Extrusion, Spindle MountM8 Star Washer24
Y Plates to X-Axis Extrusion / End Plates to Y Extrusion, Spindle MountM8x25 SHCS-24
Securing Y Rails to BaseM8x40 SHCS12

Other Parts


PartDescription1000mm Qty1500mm Qty
T5B10T5_Delrin Idler33
DCDrag Chain / m33
Z ACMEZ-Axis Acme Thread 202mm11
T5P10T5 Pulley 10-15 tooth With flange44
T5P20T5 Pulley 20-24 tooth With flange11
FBFlanged Bearing22
CNCoolant Nozzle (T-slot Bed Option Only)11
MBCMisumi Black Cap 204044
Gusset Set for 4040Set of 8 Gussets11
SpindleNone, 800W, 1.5 KW, 2.2kw as per option selected11
Spindle Mount80mm Spindle Mounts if spindle option selected11
NEMA23_76Stepper Motors Nema 23 – 76mm Single Shaft44
CPCoolant Pump (Qty 2 if T-slot bed option is taken)11
BeltAT5 Open Belt – meters7.510
BeltAT5 Closed Loop Belt11
DTDrip Tray – (With T-slot Bed Option)9901400
DCBDrag Chain Brackets222


Things you will need to complete the build

  • Soldering Iron
  • Basic Hand Tools
  • A couple of tubes of clear kitchen/bathroom silicone (T-slot Bed Option)
  • Support from an Electrician to commission the 240V components.

Electronic Components

Depending on the options you have selected the electronics kit may include one of the following:

  • GRBL AIO & Associated Connectors
  • Masso Controller & Associated Connectors
  • Gecko G540 Driver Board  & Associated Connectors / Cooler Etc


All Kits include a minimum of the following Electronics

Electronics Enclosure1
Neutrik PowerCon Plug & Socket1
Din Rail1
12V Power Supply1
12V Fan & 2 * Dust Filter1
Cable Ties & Sticky MountsAssorted
DC PSU Cable1m
2.5mm AC Power Cable Red, Black, Green1m
Wiring harness Motors4
X&Y limit cables Harness2
Z limit cable Harness1
Emergency stop switch1
Large cable gland2
Medium cable gland2
Small cable gland2
Cable Sock5
Large Cable Sock10m
Medium Cable Sock2m
Small Cable Sock2m
Variable Frequency/Speed Drive /(With Spindle Option Only)0/1
12V Bilge Pump (Water Cooled Spindles Only)0/1
2 x DC Power supplies, electronics option dependant2
Shielded 4 Core VFD Spindle Cable7m


Variable Frequency/Speed Drive (VFD / VSD)

Your inverter must be installed by a Licensed Electrician – these notes are for the electrician.


  • Your inverter must have a ground connection.
  • Your spindle will die, very quickly, without coolant flow, don’t run it without first setting up the coolant pump!  (Relevant to Water Cooled Models Only)
  • Setup the VFD parameters before running the spindle!
  • There is no polarity to the spindle connections. Active outputs from the VFD connect to any of pins 1, 2 & 3 on the Spindle. The Spindle will run in an arbitrary direction.  You want it to run clockwise when looking from above. (Above when the spindle is mounted!). If the spindle is not turning clockwise, you can simply swap over any two of the 3 active spindle connections at either end.   Just pick two of the three active wires and swap them, clearly not the ground line it must stay connected to pin 4 on the spindle.
  • Shielded Cable is provided to help keep this noisy appliance from interfering with the limit switch signal lines.
  • The front panel of the VFD can be removed and a PC network cable used to mount the control panel in a convenient place.
  • Do not run the spindle without first ensuring the coolant is flowing to it(water-cooled only)  and setting these parameters!


Heavy Mill Assembly.

  • The assembly of your Heavy Mill is not overly dependent on the order.
  • Please set the short videos on loop as you assemble each part.
  • The pre-build notes in the next section may save a lot of difficulties, read before starting assembly

Regarding Hardware: 

  • As a general rule, if it fits its the right bolt, nut or screw – it will fit don’t force it
  • There are several washer types included which provide different support. The Spring Washers help maintain pressure on the joint to reduce vibrations loosening the connection and the star washers to help keep the assembly in a position where the bolt may be in a slot and not a hole. We tend to use both a star and a spring in the slotted holes – although this may be unorthodox.
  • There are considerable spares included, you should not need to find a hole for all of these
  • Following the short videos and cross-referencing the hardware list above to select the right hardware for the assembly.

 Regarding Electronics:

  • It’s very important to have electricians support for commissioning.
  • The VFD cable supplied is an important part – its difficult to make use of such a thick cable however it has been designed for the tough job and should not be substituted.

Pre Build Notes:

The Linear Bearing blocks used on the X & Y axis need to be carefully installed.

There is a small black spacer inserted into the bearing, it’s not to be pulled out – doing so will release all the balls all over the floor and repacking is quite an episode.   Never remove the black spacer strip unless it’s a rail that’s pushing it out and taking its place!

The tolerances of these bearings are very tight.   Where two bearing blocks must be used together the bolts securing the bearing blocks must be left loose.   Should the bolts be tight and there be no play in the alignment of the blocks, the rail will not be able to be slid through both blocks. In the image below as the rail attempts to enter the second block – it had better be perfectly aligned or left loose. Otherwise at this point will need to be backed out and realigned and it’s a tough job to feed the black spacers back into the blocks carefully while retrieving a heavy rail out of the block!

CAD Video of how the install and remove rails without loosing balls

Stepper Motors

  • Never disassemble the stepper motors, after doing so they are ruined – if something is wrong with a stepper, its wiring or driver-based – nothing can be fixed by opening the motor.



Continue to Part 2