Rat Rig Mill

Electronics Options Bill of Materials Build Guide

Introducing the Rat Rig Mill - an all-metal, compact, and sturdy desktop CNC machine designed to meet the demands of hobbyists, makers and fabricators.

Rat Rig Mill - Machine Kit

Machine Kit: Includes all structural, mechanical, and motion components. This is the core of your build.

If you'd like to check the specific components included, you can review our official Bill of Materials:

Official Bill of Materials

ELECTRONICS OPTIONS

Each bundle includes all the necessary power supplies, wiring & connectors for a complete and well thought out wiring layout.

If you'd like to check the specific components included in the Electronics Bundle Options, you can review our official Bill of Materials:

Official Electronics Bundle Options Bill of Materials

Intermediate Bundle

Optimised for use with a broad range of materials with high precision:

Woods
MDF
Acrylics
PVC
Foams
Aluminium
Brass
Copper
Can take occasional light jobs with steel

Tool: 2.2Kw full size 80mm Spindle

Includes a VFD unit (Variable Frequency Drive), which allows you to program different rotation speeds while in operation
High precision tool
Water cooling system prevents the motor from overheating even after prolonged and intensive use
Includes ER20 Collet set

Controller:

Rat Rig Rodent
Features integrated stepper motor drivers

Compatible Firmware:

FluidNC
GrblHAL

Intermediate Bundle includes:

Full size 2.2kw 80mm GPenny Bullet Spindle
Huanyang VFD
⁠Water cooling unit
Two CNC machined aluminum spindle mounts
LDO High Torque Stepper motors (345oz-in)
350watt PSU
⁠Contactor for safe E-Stop
All wiring and connectors

The intermediate bundle assembled inside the Universal Electronics enclosure

Product walkthrough

For a more detailed look check the video below.

All Metal Construction

All metal construction, no plastic on structural or kinematic components.

40 series extrusion-based frame

The 40 series extrusion based frame, M8 fasteners, and the full size XY plates provide a sturdy and stable platform for your work, allowing you to cut aluminium and steel. The double MGN15 rails with double carriages and TR8x8 lead screw transmission on the X and Y axes ensure smooth and precise movement. On the Z-axis, the TR8x4 lead screw, along with the holding torque of the stepper motor, prevents the axis from dropping when unpowered.

Bellows

Bellows protect moving parts from dust and debris, keeping the machine precise and reliable over time.

FULL-SIZE SPINDLE and milled aluminium Spindle mount

If you are a heavy-duty user, you can choose the Advanced Electronics Bundle which features a Full size 2.2KW / 80mm spindle and VFD, for a no compromises experience. For lighter work, you can choose the basic electronics bundle for a sub 1000€ fully capable mill. The super rigid Rat Rig Spindle mount, made from aluminum and available in various diameters, opens the possibility of working with a wide range of tools and materials with ease and efficiency.

Inductive Endstops

High Torque Stepper Motors

Multiple accessories:

Fixture Plate

Mill Enclosure

NOTE: Rat Rig Mill Enclosure is no longer available. Bill of materials available to self-source here.

Mill Workbench

Cuttable Materials

Metals: Aluminium, Steel, Brass, Copper
Plastics: All plastics suitable for CNC machining
Composites: Carbon fiber, MDF, particle board, etc

Machine Specifications:

Work Area X/Y/Z: 360mm x 160mm x 116mm (z-clearance 173mm)

Operational dimensions X/Y/Z: 1095mm x 715mm x 717mm

Linear Rails:
X 2x MGN15 with double carriages
Y 2x MGN15 with double carriages
Z 2x MGN15 with double carriages

Transmission:
X Leadscrew - TR8x8
Y Leadscrew - TR8x8
Z Leadscrew - TR8x4

Linear movement precision:

X - 0.0025mm
Y - 0.0025mm
Z - 0.0025mm

Build Guide

An on-line step-by-step build manual with detailed images, diagrams and instructions is available here.

CAD Models

Rat Rig Mill - Intermediate with Universal CNC Electronics Enclosure

BILL OF MATERIALS

Mill BOM

Electronics Bundle BOM

Community Support

Join our communities and connect with other Rat Rig CNC Machine users:
Facebook community
Discord community

Acknowledgements

It's through the collaborative spirit and shared knowledge of the open-source community that innovations like ours are possible. Our design is a testament to the cumulative progress made by many, and we are proud to stand on the shoulders of giants. Regarding the Mills in specific, we'd like to acknowledge the invaluable contributions made by OpenBuilds and Millennium Machines. We aim to celebrate the collective achievement of the open-source community and continue contributing to this vibrant ecosystem.

CNC Machines