Spindle Control Isolator Board

The Sherline/Acorn CNC Controller is a fully integrated, plug-and-play control designed for Sherline CNC machines and compatible third-party systems. It combines the industrial Centroid Acorn CNC control with a custom Sherline housing, wiring, and connectors to simplify installation, upgrades, and retrofits. Centroid CNC, founded in 1979 in Howard, PA, produces high-performance, industrial-quality CNC controls. The Acorn controller is an excellent upgrade for both new and older Sherline CNC machines, including legacy systems originally supplied to OEMs such as Denford, D&M, LabVolt, Paxton-Patterson, and Light Machines (Spectralight).

[icon icon=icon-chevron-down size=14px color=#000 ] Controller Features

Custom control housing includes:

• Centroid Acorn CNC control board
• Acorn plug-and-play relay module (mounted and pre-wired)
• Internal wiring to DB9, DB25, and 2-wire Molex connectors
• Power supply, push-to-reset circuit breaker, and cooling fan
• External Ethernet port, power switch, and power LED

Front panel connections:

• Ethernet connection
• Power switch and power LED
• Cooling fan

Rear panel connections:

• Three DB25 connectors:
  • Sherline 4-axis driver box
  • Aux 4-axis control for additional drives/axes
  • Relay card
• Three DB9 connectors:
  • Limit switches
  • External encoder*
  • Aux tool setter or touch probe (one at a time)
• Three 2-wire Molex connectors:
  • E-stop button
  • Spindle control
  • Laser

Power & cabling:

• Dual logic power: 5 VDC and 24 VDC
• Input power: 100–120 VAC or 208–240 VAC, 50/60 Hz
• 15 ft shielded Ethernet cable (controller to PC)
• External E-stop with 2 ft cord

*For spindle speed-control information, see: Sherline/Acorn Spindle Speed-Control Information .

[icon icon=icon-chevron-down size=14px color=#000 ] Compatibility & Connection Options

• The controller connects directly to Sherline 24 V stepper motors via the Sherline 4-axis driver box (P/N 8760).
• Not compatible with MASSO 36 V closed-loop stepper motors.
• For DIY users with their own motors/drives, use the “Aux 4-axis” DB25 connector. Wiring information for DIY customers is available under the Specifications/Downloads.

You can use the controller with or without limit switches. CLICK HERE for more information on limit switch assemblies for Sherline lathes and mills .

[icon icon=icon-chevron-down size=14px color=#000 ] Software & Conversational CAM

A free version of Centroid CNC12 is included with each Acorn kit for initial setup. However, it is strongly recommended that you purchase the Centroid Acorn “Pro” CNC12 Software License to unlock full conversational CAM (Intercon). Use the options below or visit: CLICK HERE for Acorn “Pro” CNC12 Software License details Intercon Conversational CAM:

• Program directly from hand sketches or prints
• Import DXF files and generate G-code without separate CAD/CAM
• Ideal for new CNC users and those unfamiliar with traditional G-code programming

Recommended training videos:

• Centroid CNC Control User Training Video: CNC Milling Machine Training
• Centroid DXF Import Using Intercon Conversational Software
• Centroid Acorn Lathe Conversational Programming Primer

[icon icon=icon-chevron-down size=14px color=#000 ] Typical Use Cases

DIY Customer

• Buys CNC-ready Sherline machines and installs their own motors, drives, and encoders.
• Purchase the base Sherline/Acorn CNC Controller (P/N 9400) without options and wire to your own hardware.

CNC Upgrade Customer

• Upgrading an existing Sherline CNC system including older OEM systems such as Denford, D&M, LabVolt, Paxton-Patterson, or Light Machines. For a sample Denford/Sherline Microlathe conversion using Acorn, see: Centroid Denford/Sherline Microlathe Conversion
• If you already have a Sherline Linux PC or 4-axis driver box, configure the controller with:
  • Spindle Control Isolator Board
  • External Encoder kit for your headstock (Standard or 3C)

CNC Turnkey Customer

• Wants a complete Sherline system: CNC-ready machine, 24 V stepper motors, 4-axis driver box, spindle control isolator board, and external encoder.
• The Sherline/Acorn Controller is designed to support all of these configurations.

Additional documentation and support are available on the Centroid Community CNC Support Forum .

[icon icon=icon-chevron-down size=14px color=#000 ] Important Notes for Spindle Control

• To control spindle speed via G-code, you must have a motor drive or the Spindle Control Isolator Board and an external encoder installed.
• These components work together to accurately acquire and control spindle RPM.
• If you do not include the Spindle Control Isolator Board at the time of purchase, adding it later will require returning the controller to Sherline for installation. Email orders@sherline.com for return instructions.

For detailed spindle control information, download: Sherline/Acorn Spindle Speed-Control Information . Lead Time: Approximately 3 weeks