The CNC Workshop

You command 18,000 RPM, but the VFD displays 300. Is the spindle actually running at the wrong speed—or is the VFD showing frequency in hertz instead of RPM?

In Episode 8, Daniel and Jamie explain how to separate a harmless display misunderstanding from a real spindle-speed problem. They walk through controller scaling, minimum-frequency limits, PWM and analog signals, Modbus communication, VFD command sources, motor parameters, and unexpected S commands in your g-code.

You’ll also learn a practical troubleshooting sequence for comparing controller operation, VFD keypad control, and job-file behavior without randomly changing parameters.

Read the companion article:
https://pwncnc.com/blogs/news/cnc-spindle-running-wrong-rpm

The CNC Workshop is presented by PwnCNC.

A running pump doesn’t always mean coolant is circulating through your CNC spindle.

In this episode, Daniel and Jamie explain how to keep a water-cooled spindle running safely and reliably. They compare pond-pump reservoirs with CW-3000 chillers, discuss the recommended 85% distilled water and 15% Nu-Calgon Freez-Kontr’l baseline, and explain why colder coolant is not necessarily better.

You’ll also learn how to:

• Protect the cooling loop from freezing
• Clear bubbles and airlocks
• Diagnose weak or missing coolant flow
• Find leaks before they reach electrical equipment
• Respond to chiller alarms
• Build a simple pre-job cooling check

Whether you already own a water-cooled spindle or are deciding between air and water cooling, this episode will help you understand the maintenance commitment and avoid expensive failures.

Read the complete companion guide:
https://pwncnc.com/blogs/news/cnc-spindle-cooling-coolant-chillers-winter-storage-leaks

The CNC Workshop is presented by PwnCNC.

How does your CNC controller actually tell a VFD-controlled spindle to start, stop, or change speed?

In this episode of The CNC Workshop, Daniel and Jamie trace the complete control path from the CNC software and controller hardware to the control cable, VFD, spindle cable, and motor.

They explain the differences between PWM, analog voltage, and Modbus/RS-485 control—and why a cable that physically fits may still be electrically wrong. The conversation covers common Buildbotics and Onefinity Black Box configurations, custom LinuxCNC and Mesa installations, Mach4 and Avid systems, and Sienci SuperLongBoard and SLB-EXT controllers.

You’ll also learn what to check when the VFD works manually but not from the CNC, the commanded RPM is incorrect, communication lights never flash, reverse will not operate, or a factory reset creates new problems.

Read the complete companion guide, including the compatibility checklist and troubleshooting table:

https://pwncnc.com/blogs/news/cnc-spindle-controller-wiring-guide

The CNC Workshop is presented by PwnCNC.

Your coolant pump is running—but is coolant actually circulating through the spindle?

In this episode of The CNC Workshop, Daniel and Jamie explain how to troubleshoot a water-cooled CNC spindle with no return flow, a weak trickle, or air bubbles that refuse to clear.

You’ll learn how to:

• Test the pump independently
• Find restrictions in tubing and quick-connect fittings
• Purge stubborn airlocks
• Perform a spindle bypass test
• Flush a restricted cooling passage safely
• Recognize when a pump, fitting, or spindle may need replacement

A humming pump does not prove that coolant is moving. Do not operate a water-cooled spindle until you have confirmed steady circulation through the return line.

Read the complete troubleshooting guide:
https://pwncnc.com/blogs/news/water-cooled-cnc-spindle-troubleshooting

The CNC Workshop is presented by PwnCNC.

Should you upgrade your CNC with a 110V or 220V spindle?

In this episode of The CNC Workshop, Daniel and Jamie explain what the voltage actually changes—and why the larger number is not automatically the better choice.

You’ll learn:

• When a 1.5kW 110V spindle is likely all your machine needs
• When a 2.2kW 220V system provides useful power headroom
• Why spindle weight, mount diameter, ER11 versus ER20 tooling, and machine rigidity matter
• How the spindle, VFD, electrical circuit, and CNC controller must work together
• Why VFDs can cause nuisance tripping with some plug-in GFCI devices
• Why required GFCI protection and equipment grounding should never be bypassed

Before paying for the biggest spindle available, make sure your machine and workshop can actually use it.

Read the complete companion article:
https://pwncnc.com/blogs/news/110v-vs-220v-cnc-spindles

The CNC Workshop is presented by PwnCNC.

Your CNC spindle suddenly stops, and the VFD displays an angry little error code. What does it mean—and what should you check before assuming something has failed?

In Episode 3 of The CNC Workshop, Daniel and Jamie explain how to approach common CNC VFD faults without simply clearing the code and hoping it disappears. They discuss:

• Why a VFD error code is a clue—not a complete diagnosis
• ERR09 undervoltage faults and possible power-supply problems
• ERR12 input phase-loss faults and wiring checks
• ERR31 or 031 communication and control-signal issues
• ERR38 current-detection and hardware-related faults
• What a blank VFD display may indicate
• Why the timing of a fault matters
• The difference between faults occurring at startup, during acceleration, and while cutting
• What information to collect before contacting technical support
• When troubleshooting should stop and professional support should begin

You’ll also learn why repeatedly resetting a fault can hide useful clues—and why opening a VFD or changing parameters without a plan can create additional problems.

This conversation is based on real troubleshooting questions received by the PwnCNC support team.

Explore PwnCNC spindle systems, VFD packages, and technical resources:
https://pwncnc.com

Read the companion article:

The CNC Workshop is presented by PwnCNC.

Does an automatic tool-changing spindle require a MASSO controller? Not necessarily—but controlling spindle speed is very different from safely coordinating a complete automatic tool change.

In Episode 2 of The CNC Workshop, Daniel and Jamie explain what a CNC controller must actually do to support an ATC spindle. They discuss:

• Why an ATC spindle can sometimes run without automatic tool changing
• The difference between spindle control and full ATC control
• Tool-release outputs, sensors, macros, probing, and safety logic
• Why controller compatibility must be confirmed before purchasing
• When a MASSO controller or controller conversion may make sense
• How PwnCNC Core and Advanced MASSO conversion kits fit into an upgrade plan
• Questions to ask before combining an ATC spindle with a third-party controller

The key takeaway: MASSO is not the only controller capable of supporting an ATC spindle, but the controller must be able to manage the entire tool-change process—not merely start, stop, and adjust the speed of the spindle.

This conversation is based on real compatibility questions received by the PwnCNC support team.

Explore PwnCNC ATC systems and controller upgrades:
https://pwncnc.com

Read the companion article:

The CNC Workshop is presented by PwnCNC.

Thinking about replacing your CNC router with a spindle? Before you order, you need to know whether the spindle, mount, VFD, controller, electrical service, control cable, drag chain, and dust collection will actually work together.

In the first episode of The CNC Workshop, we walk through 10 important compatibility checks to make before buying a CNC spindle.

We discuss:

• 65mm versus 80mm spindle mounts
• 110V versus 220V spindle systems
• Choosing the appropriate spindle power
• PWM, analog, and Modbus control
• VFD control cables and controller compatibility
• Drag-chain capacity and cable routing
• Dust-boot and Z-axis clearance
• Requirements for automatic tool changing
• When a controller upgrade may be necessary
• What existing PwnCNC equipment may be reusable

This conversation is based on real compatibility questions received by the PwnCNC support team.

Explore CNC spindle systems and upgrade options:
https://pwncnc.com

Read the companion article: https://pwncnc.com/blogs/news/cnc-spindle-upgrade-compatibility

The CNC Workshop is presented by PwnCNC.