GS:TE 4-Meter External Thread Grinder

Drake GS:TE 4-Meter Ballscrew Grinder

The world’s first 4-meter linear motor ballscrew grinder

The GS:TE 4-Meter has a grind length of 4-meters and swings over 350mm.

The machine has a cast polymer base with moving wheel head design and no mechanical drives on the principal axes. The wheel in feed (X-axis) and work traverse slide (Z-axis) are driven by linear motors. The work head (C-axis) is driven by a torque motor integral with the spindle and boasts a better than 10 arc seconds index accuracy.

This massive machine for grinding ball screws (and nuts with the internal attachment) operates with no ball screws–truly a “mother” machine tool.”

A recent runoff for a customer consisted of grinding a 790 mm ISO Class 0 (lead error of less than +/- 7microns in the length) ball screw as well as a 3.5 meter ISO Class 1 ball screw (lead error of less than +/- 32 microns in the length) both ground in one setup without removing either screw for lead inspection during the grind.

Drake GS:TE 4-Meter Grinding a ball nut with internal attachment

Drake GS:TE 4-Meter Ballscrew Grinder for HMT Machine Tools

Drake GS:TE 4-Meter grinding long ballscrew

Other GS:TE 4-Meter Thread Grinder features include:

  • Two-axis, behind-the-wheel dresser
  • Headstock mounted dresser with outboard bearing support for crushing or form roll dressing
  • Power helix
  • Internal grinding capability
  • On-machine inspection via Renishaw probe
  • Drake PartSmart™ software programs for customer parts


Tailstock and Wheel Head Wheel

The worktable is equipped with a precision tailstock with manual adjustment for product lengths from 25mm to full travel length. A pneumatic powered quill with male, carbide-tipped, Morse taper center is provided. Tailstock position feedback provides the operator with indications of work piece thermal growth during the grind process via a positioning sensor.

Steady Rest

Steady Rests.
The machine is equipped with 6 manual 3-point steady rests for centering and supporting long parts during the grind cycle. The Fanuc control is equipped with steady-rest compensation software for CNC taper correction. Additional steady rests are available as well as hydraulic, self centering, follow-down steady rests. Standard rest jaws are provided for 20-100mm diameter work.

Diamond Roll Contour Dresser

Diamond Roll Truing.
A 2-Axis (W- and Y-axes) electric motorized rotary diamond dressing unit is mounted in the wheel head behind the wheel or on the work head depending on the machine configuration required. Wheel forms are generated by simultaneous CNC contouring on W- and Y-axes or by plunging with a form roll. One diamond contouring roll included. Optional Acoustical Emissions Monitoring (AEM) is available.

Work Piece Range:
Work Length Between Centers (Max) 4200 mm
Grind Length Maximum 4000 mm
Thread Diameter Maximum 300 mm
Work Diameter Swing (Max) 440 mm
Work Piece Weight (Max) 400 kg
Internal Grinding Optional
Thread Range:
Programmable Lead 0 to 999 mm
Lead Angle Range ±40°
Programmable Thread Starts 999
Contour Dress Thread Forms 60º, 55º, Acme, Trapezoid, Buttress, Gothic Arch, Radius, ISO, DIN, Whitworth, API, Others.
Dressing Methods Diamond contour or form roll, single or multi-rib
Form Width x Depth 25 mm x 18 mm
Wheel Spindle:
Wheel Spindle Power 22 kW
Wheel Peripheral Speed (vc is constant) 50 m/s new wheel
Wheel Spindle Bearing Construction Hydrostatic/2000 RPM max
Standard Grinding Wheel Range:
  Outside Diameter (Spent Wheel) 500 mm (400 mm)
  Width 12 to 70 mm
Number of CNC Axes 6 (includes helix)
Work Head Motor (C-axis) Fanuc Torque Motor
Work Head Speed Up to 200 rpm
Work Head Positioning Encoder ±2 arc seconds
Work Spindle Thru Hole Diameter 150mm
Work and Wheel Axes (X, Z) Fanuc Linear Motors
Dresser Cross and Feed (Y,W) Fanuc Servo & Ball Screws
Linear Axes Position Feedback 0.05 micron Heidenhain Scales
Wheel Head Angle (A-axis) Fanuc Servo & Gear Set
Linear Ways Rails and Recirculating Roller Cars
Base Construction Cast Polymer
CNC Fanuc 31i
Voltage 200-600 V
Total Electrical Requirements 52 kVA
Weight 30,000 kg
Machine Dimensions:
Overall 7.4m W x 2.4m D x 2.4m H
Work Holding Height 1.4 m above floor
Coolant Discharge Height 0.35 m above floor
Machine Color RAL 9003 Signal White or specify
Guards Stainless Steel, LEXAN
Minimum Grind Coolant Requirements:
Grind 80 lpm @ 7 bar
Bed Wash 50 lpm @ 1-2 bar
Total Flow 130 lpm
Diamond Dressing Rolls:
Diameter 114 to 125 mm
Width Up to 32 mm
Bore 52 mm