Mori Seiki MS-850G Heavy Duty Gap Bed Engine Lathe

17" / 25" x 33" Capacity | Precision Toolroom Grade | Made in Japan

Overview

The Mori Seiki MS-850G is widely regarded by master machinists as the finest manual engine lathe ever produced. Engineered for extreme rigidity and "silk-smooth" operation, the MS-850G is a heavy-duty powerhouse that holds tolerances far better than modern light-duty machines.

This is a Gap Bed model, providing a standard 17" swing for precision work, with the ability to remove the gap for a massive 25" swing on large-diameter flanges and repair work. At approximately 4,500 lbs, it offers the vibration dampening required for superior surface finishes in the toughest materials.

Technical Specifications

• Swing Over Bed: 17.13"
• Swing In Gap: 25.5" (Removable Gap)
• Distance Between Centers: 33.46"
• Swing Over Cross Slide: 9.84"
• Spindle Bore: 2.05" (52 mm)
• Spindle Speeds (12): 32 – 1,800 RPM
• Spindle Nose: A1-6 (Precision Ground)
• Threading (Inch): 4 – 80 TPI (40 changes)
• Threading (Metric): 0.5 – 7.0 mm
• Feeds (40): 0.0018" – 0.025" IPR
• Main Motor: 5 HP, 220V/440V, 3-Phase
• Bed Width: 13.75" (Induction Hardened & Ground)
• Machine Weight: Approx. 4,500 lbs

Key Features & Benefits

• Legendary Japanese Build: Mori Seiki lathes are known for superior metallurgy. The hardened bed ways and precision-ground gears in the headstock ensure a lifetime of service.
• Geared Headstock: 12-speed selection with high-torque delivery, running in a continuous oil bath for quiet, cool operation.
• Foot Treadle Brake: Includes an integrated mechanical foot brake for immediate spindle stopping—essential for safety and high-efficiency threading operations.
• Large Spindle Through-Hole: The 2-inch bore allows for long shafting and bar work to pass through the headstock with ease.
• Massive Carriage & Tailstock: The oversized carriage provides maximum stability during heavy cuts, while the #4 Morse Taper tailstock ensures rigid support for long-workpiece drilling and centers.

Condition & Investment Value

The Mori Seiki MS series is considered "investment-grade" machinery. Unlike newer imports that lose value instantly, a well-maintained MS-850G is a stable asset that continues to command high prices in the secondary market due to the lack of modern equivalents with this level of mass.

Dealer Note: If you are looking for a machine that bridges the gap between a toolroom lathe and a production powerhouse, the MS-850G is the industry standard. It is the "forever lathe" for any serious shop.