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Heavy Mill Build Part-1

Originally published at: https://www.3dtek.xyz/2015/12/19/heavy-mill-build/

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 support@3dtek.xyz 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 Parts Description QTY
SCP Spindle Carriage 1
YPA Y_Plate_Type_A 2
YPB Y_Plate_Type_B 2
XHP_Top X Horizontal Top 1
XVP_Front X Carriage Plate Vertical Front 1
XVP_Back X Carriage Plate Vertical Back 1
XHP_Bot X Horizontal Bottom 1
XHP_Mid X Horizontal Mid 1
XMP X Motor Plate 1
YMP Y Motor Plate 2
XPP X Pulley Plate 1
YPP Y Pulley Plate 2
BCT Belt Clamp Top 3
BCB Belt Clamp Bottom 3
YCP Y Carriage Plate Left 1
YCP Y Carriage Plate Right 1
YCP Z Motor Mount 1

Aluminium Extrusions:



Part Description 1000mm Qty 1500mm Qty
4040 Rail 4040 Rail – Base Structure 4 6
X-Axis Rail 8080 – Tapped Both Ends M8 * 15mm 1 1
Y-Axis Rails 40120 – Tapped Both Ends M8 * 15mm + Drilled & Counterbored holes. 2 2
XDGRail X-Axis Drag Chain Support Rail 2040 T Slot 1 1
YDGRail Y-Axis Drag Chain Support Rail 2040 T-slot 1 1

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


Part Description 1000mm Qty 1500mm Qty
Bed T-slot 15180 – T-slot Bed Extrusion – If bed option is taken 3 5
Bed T-slot Left Side 15180 – 4-6 holes – if bed option taken 1 1
Bed T-slot Righ Side 15180 – 4-6 holes – if bed option taken 1 1
T-Slot Tee Extrusion T-Slot Connectors – if bed option taken 4 6
Water Block Strip
12×3 MM Alloy Flat Bar strip – if bed option taken
1 1


Linear Motion

Part Description 1000mm Qty 1500mm Qty
HGW20 HGW20CC Linear Bearing Blocks 6 6
HG20 Linear Rail – ~990 / ~1490 mm 2 2
HG20 Linear Rail – ~1100 / ~1490 mm 2 2

Part Description 1000mm Qty 1500mm Qty
HSS 16mm hardened Steel Shaft 225mm 2 2
PB Pillow Bearing Blocks SC16LUU 2 2



Part/Purpose Label Code Qty
Securing Z Pully on Acme Thread M8 Flanged Nut 1
8MM Steel Spacer sits below pulley on Z Acme 8 mm Spacer 1
Idler Pulley Spacer 5mm Bore (one inside, one outside Idler) 3 mm Spacer 6
Z-Axis Lead Nut Lead Nut 1
X & Y Limit switches M3 Nylock Nut 8
X & Y Limit switches M3 Washer 8
Shaft Grubs Screws M3x10 BHCS 4
Z Limit Switch M3x16 SHCS 2
X & Y Limit switches M3x25 SHCS 8
Drag Chain to Drag Chain Support Extrusion M4 Tee Nut 4
Drag Chain to Drag Chain Support Extrusion M4x10-12 SFHCS 4
Drag Chain Mounts M5x12 BHCS 4
Belt Clamp Top M4x25 SHCS 6
Stepper Motors M5 Nylock Nut 24
Stepper Motors M5 Star Washer 16
Stepper Motors M5 Washer 16
Y Stepper Motors M5x25 SHCS 8
Z Motor Mounting M5x16 BHCS 12
Securing Bearing Rail, X Stepper Motor M5x20 SHCS 104
Bolting together all other plate hardware M5x20 FSHCS 28
Motor Plates, Pulley Plates M5x20 FSHCS 18
Belt Clamp Bottom M5x25 BHCS 6
Idler Pulley Axels M5x30 BHCS 3
Y-Axis Limit Switch Triggers M5x40 BHCS 2
X-Axis Limit Switch Triggers M5x70 SHCS 2
Bearings In Y-Axis M6 Spring Washer 16
Bearings In Y-Axis M6 Star Washer 16
Bearings In Y-Axis M6x20 SHCS 20
Bearings In X-Axis Plates M6x20 FSHCS 8
Securing Wasteboard M6 Tee Nut 30
Spindle Clamp Bolts M6x50 SHCS 4
Y Plates to X-Axis Extrusion / End Plates to Y Extrusion, Spindle Mount M8 Spring Washer 24
Y Plates to X-Axis Extrusion / End Plates to Y Extrusion, Spindle Mount M8 Star Washer 24
Y Plates to X-Axis Extrusion / End Plates to Y Extrusion, Spindle Mount M8x25 SHCS- 24
Securing Y Rails to Base M8x40 SHCS 12

Other Parts


Part Description 1000mm Qty 1500mm Qty
T5B10 T5_Delrin Idler 3 3
DC Drag Chain / m 3 3
Z ACME Z-Axis Acme Thread 202mm 1 1
T5P10 T5 Pulley 10-15 tooth With flange 4 4
T5P20 T5 Pulley 20-24 tooth With flange 1 1
FB Flanged Bearing 2 2
CN Coolant Nozzle (T-slot Bed Option Only) 1 1
MBC Misumi Black Cap 2040 4 4
Gusset Set for 4040 Set of 8 Gussets 1 1
Spindle None, 800W, 1.5 KW, 2.2kw as per option selected 1 1
Spindle Mount 80mm Spindle Mounts if spindle option selected 1 1
NEMA23_76 Stepper Motors Nema 23 – 76mm Single Shaft 4 4
CP Coolant Pump (Qty 2 if T-slot bed option is taken) 1 1
Belt AT5 Open Belt – meters 7.5 10
Belt AT5 Closed Loop Belt 1 1
DT Drip Tray – (With T-slot Bed Option) 990 1400
DCB Drag Chain Brackets2 2 2


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

Description Qty
Electronics Enclosure 1
Neutrik PowerCon Plug & Socket 1
Din Rail 1
12V Power Supply 1
12V Fan & 2 * Dust Filter 1
Cable Ties & Sticky Mounts Assorted
DC PSU Cable 1m
2.5mm AC Power Cable Red, Black, Green 1m
Wiring harness Motors 4
X&Y limit cables Harness 2
Z limit cable Harness 1
Emergency stop switch 1
Large cable gland 2
Medium cable gland 2
Small cable gland 2
Cable Sock 5
Large Cable Sock 10m
Medium Cable Sock 2m
Small Cable Sock 2m
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 dependant 2
Shielded 4 Core VFD Spindle Cable 7m


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