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Charter Oak Automation

CNC Controlled Machinery for Industrial and Serious Hobbyists

Charter Oak Automation
424 Grand Avenue
New Haven, CT 06513
(203) 562-0699

Home » Charter Oak Automation Products » High-Capacity Square Column Manual Bed Mill

High-Capacity Square Column Manual Bed Mill

Available Features and Pricing:

12Z Square Column Manual Mill: $2,350.00
Available Upgrades:
3 HP VFD Spindle Motor: $850.00
Mach-1 Quick Change Tooling System (Start-Up): $995.00
Mach-1 Quick Change Tooling System (Complete): $1,495.00
Heavy Duty Stand: $375.00
Easson ES-8A 3-Axis DRO (5 µm Res.): $799.00
Fagor 30i 3-Axis DRO (0.1 µm Res.): $2,173.90
Fagor 40i 3-Axis DRO (0.1 µm Res.): $2,425.90
X-Axis Powerfeed: $457.43
NT30 Spindle: $325.00

To Order or Request More Information:

Phone: (203) 562-0699 Email:

Our manual mill offers a large working envelope in a small footprint. The extensive range of upgrades lets your mill keep pace with your needs as they grow over time, or can be factory-installed at no extra cost if they are purchased at the time of your original order.

Product Information:

Product Overview Trifold (PDF)

Popular Upgrades:

Mach-1 Quick Change Tooling System
3 HP Sensorless Vector VFD
NT30 Spindle
DRO (Digital Read-Out) Systems

Product Features

  • Working envelope equivalent to a full-size knee mill in a smaller footprint.
  • Increased rigidity and accuracy due to square column, dovetail ways, and internal ribbing.
  • Six-speed gear box lets you select the right speed for your material and cutting tool.
  • Single-phase power requirements are perfect for small shops and home hobbyist applications.
  • Powerful 2 HP motor, upgradeable to a 3 HP variable-frequency drive.
  • Larger table size than other square column bed mills.
  • Hardened head gears for improved reliability.
  • Dial markings in inches (metric is available with extra lead time; call for details).
  • Improved head rigidity with a Z slide length of 12½” and a 12¼” diameter head mounting collar. That equates to an increased Z-axis slide of 66% over other mills (most others are 7½”) and increased head collar contact area of 185%.

Square Column Bed Mill Specifications:

Working Envelope Details:
Total Travel (Volumetric): 6,864 in3
X-Axis (Longitudinal Table Travel): 26"
Y-Axis (Cross-Table Travel): 12"
Z-Axis (Quill Retracted): 22"
Quill Travel 4¾"
Table Details:
Table Work Surface (Linear): 39½" × 9⅜"
Table Work Surface (Areal): 370.3125 in2
T-Slots: 3 Slots, ⅝” Each
Spindle Motor Details:
Standard Power: 2 HP
Standard Speeds (RPM): 100, 190, 330, 480, 910, 1600
VFD Upgrade Power: 3 HP
VFD Upgrade Max Speed (RPM): 3,600
Spindle and Quill Details:
Spindle Taper: R8 or NT30
Spindle Center to Column: 12½"
Spindle to Table (Min, Quill Retracted): 3"
Spindle to Table (Max, Quill Retracted): 22"
Quill Diameter: 3"
Miscellaneous Details:
Head Rotation: ±90°
Power Requirements: 220-240V AC, 50/60Hz single phase
Lead Screw Measurements/Dials: Imperial (Inches)
Weight: 770 lbs.
Required Floor Space for Max Travel: 90" H (with stand) × 87" W × 38" D

A Mill That Keeps Pace With Your Growing Needs

Purchasing a new mill is an investment in the future. For business owners, an efficiently used mill will increase productivity and profit. For hobbyists, it provides finer control over your craft. And for educators, it is an investment in the next generation of machinists. But no matter what use our mills are put towards, your machining needs tend to grow over time. That’s why we provide a diverse range of upgrades that lets your investment keep pace with your changing needs.

Mach-1 Quick Change Tooling SystemMach-1 Quick Change Tooling System

The most popular quick change tooling system has been adapted by Mach-1 Systems Inc. specially for our mills. Swapping a tool takes only seconds, with just a small push on the quill lever—no wrenches or awkward reaching needed!

The patented Mach-1 system replaces the standard draw bar in our mills, gripping your tools with 600 lbs. of holding force. Tool length offsets are retained between collet changes, increasing your time efficiency and reducing human error. For industrial customers, the payback period from time savings alone can be as short as a few months at typical shop rates.

3 HP VFD3 Horsepower Sensorless Vector Variable Frequency Drive

When you need more power and speed at the spindle, our 3 HP sensorless vector VFD spindle motor provides it. The VFD increases our mill’s maximum spindle speed to 3,600 RPM.

But maximum speed isn’t everything. The optimum cutting speed varies by material, pass depth, and cutting tool. Furthermore, no spindle motor’s output torque remains constant at all speeds, so low-RPM and high-RPM horsepower suffers without a matching mechanical advantage. A VFD lets you select any spindle speed you want, but in conjunction with our six-speed gearbox you can stay closer to the top of the torque curve than with competing mills that offer fewer gear or pulley ratios.

Our VFD uses sensorless vector technology, which yields improved torque and more speed consistency as you approach zero RPM compared to other VFDs and helps to improve your machining results for slow operations like tapping. The cooling fan is electrically powered rather than manually coupled to the shaft, so it maintains a constant flow of air even at low RPM to prolong the life of the motor. 

NT30 SpindleNT30 Spindle

Tooling for our standard R8 spindle has the advantages of being inexpensive and easily obtained, but some jobs require more spindle rigidity and resistance to side-loading forces. When you need bigger tooling or larger cutting passes to improve your machining efficiency, our NT30 spindle upgrade lets you get the job done faster.


Fagor 30i DRO SystemFagor 30i 3-Axis Digital Read-Out System

Integrating a DRO into your mill lets you immediately position your workpiece accurately and precisely, minimizing the use of calipers, micrometers, and other gauges. This lets you realize extraordinary time savings, and reduces the frequency of human error.

Fagor 40i DRO SystemFagor 40i 3-Axis Digital Read-Out System

The Fagor 40i DRO system offers similar advantages to the 30i model, but provides a more intuitive interface through a full-color TFT screen. The programming assistance offered in the 30i model is graphically displayed in on-screen diagrams, and the results of the programmed operations can be displayed in 3D using machine simulation.
Fagor 40i Technical Information (PDF)

Our DRO systems additionally provide programming assistance, telling you where your next coordinates should be for the following operations:

  • Bolt-hole patterns
  • Linear drilling
  • Grid drilling
  • Milling pockets
  • Finding angles from the horizontal

For customers who need to work in metric units but don’t want to wait for a custom mill order, or for customers who frequently switch between measurement systems and want to minimize calculation errors, a DRO system provides immediate measurements in both metric and imperial units regardless of the lead screw dial indicator units.