JTEKT Toyoda GL4i-50

$150,000 - $250,000 Updated 2026-03-11

Key Specifications

Weight

4,000 kg (8,800 lb)

Rapid Traverse

10,000 mm/min (394 IPM)

swing over table

320 mm (12.6 in)

distance between centers

500 mm (19.7 in)

max grinding diameter

300 mm (11.8 in)

max workpiece weight

150 kg (330 lb)

Overview

The JTEKT Toyoda GL4i-50 is a production-grade CNC cylindrical grinder built for dedicated OD grinding in high-volume environments. It's the smallest footprint option in the GL4i lineup, with 500 mm (19.7 in) between centers and a 320 mm (12.6 in) swing over the table. If you're grinding shafts, pins, or bearing journals at volume and need sub-micron repeatability shift after shift, this is the class of machine that gets it done.

The heart of the GL4i is JTEKT's patented STAT BEARING — a hybrid hydrostatic/hydrodynamic wheel spindle that eliminates metal-to-metal contact inside the bearing. That means no wear on the spindle bearing itself, ever. Rotational accuracy sits at 0.016 microns, and the spindle maintains that performance over thousands of hours without degradation. Pair that with hydrostatic ways on the wheelhead slide and you've got a machine that holds size without chasing adjustments.

The wheelhead accepts a 405 x 127 mm (16 x 5 in) grinding wheel in the standard plain configuration, or a 455 x 127 mm (17.9 x 5 in) wheel in angular setup. Max wheel width is 75 mm (3 in) standard, expandable to 100 mm (4 in) depending on configuration. Wheel surface speed runs at 33 m/s (6,500 SFPM) standard, with a 45 m/s (8,860 SFPM) high-speed option available. The 3.7 kW (5 hp) wheel spindle motor handles most production grinding; a 5.5 kW (7.4 hp) motor option is available for the high-speed configuration.

Workhead speed is variable from 21 to 500 RPM, giving you plenty of range for different workpiece diameters and materials. Max grinding diameter is 300 mm (11.8 in), and max workpiece weight between centers is 150 kg (330 lb). The wheelhead manually swivels to 0, 30, or 45 degree positions on the GL4i-50 Switch variant, letting you handle both straight and angular grinding on one machine without dedicated setups for each.

JTEKT's low thermal displacement bed design and heat isolation cover technology keep the machine thermally stable through long production runs. The bed casting is engineered to minimize thermal growth, and the heat covers prevent radiated heat from the wheel spindle motor from reaching the guideways. Minimum move increment is 0.00001 in (0.25 microns) on both the wheelhead infeed and table traverse axes. Rapid traverse runs at 10,000 mm/min (394 IPM) on both axes.

Machine weight for the -50 variant is approximately 4,000 kg (8,800 lb). Forum users consistently praise Toyoda cylindrical grinders for build quality and longevity — 'the spindle and ways will last forever' is a common refrain on Practical Machinist. They're easy to set up and user-friendly compared to some European competitors. New GL4i-50 machines typically price between $150,000 and $250,000 depending on configuration and options. Used GL4-series machines from the 2010s show up in the $40,000-$80,000 range. Specs sourced from JTEKT published data, dealer listings, and verified machinery marketplaces.

Full Specifications

Parameter	Value
Swing Over Table	320 mm (12.6 in)
Distance Between Centers	500 mm (19.7 in)
Max Grinding Diameter	300 mm (11.8 in)
Max Workpiece Weight	150 kg (330 lb)
Grinding Wheel Size	405 x 127 mm (16 x 5 in)
Max Wheel Width	75 mm (3 in)
Wheel Surface Speed	33 m/s (6,500 SFPM)
Wheel Spindle Motor	3.7 kW (5 hp)
Workhead Speed	21 - 500 RPM
Minimum Move Increment	0.00001 in (0.25 microns)
Rapid Traverse Rate	10,000 mm/min (394 IPM)
Spindle Bearing	TOYODA STAT BEARING (hydrostatic/hydrodynamic hybrid)
Spindle Rotational Accuracy	0.016 microns
Machine Weight	4,000 kg (8,800 lb)
CNC Control	TOYOPUC-GC70
Joined	Aug 15, 2011
Messages	6,918
Likes	7,861
Manufacturer	Mighty Viper
Model	VT-30GL
Horsepower	208 hp
Fuel Type	Diesel
Spindle Bore	39.69 mm

Specifications sourced from machinio.com — verified 2026-03-28

Strengths & Limitations

Strengths

STAT BEARING hybrid spindle eliminates metal-to-metal contact, delivering 0.016-micron rotational accuracy that doesn't degrade over thousands of hours of production grinding
Hydrostatic wheelhead ways provide smooth, stick-slip-free motion for consistent surface finishes and size holding across long production runs
Low thermal displacement bed and heat isolation cover technology maintain dimensional stability without relying on shop climate control alone
0.00001-in minimum move increment on both axes gives the resolution needed for sub-micron grinding tolerances on precision components
GL4i-50 Switch variant offers manual wheelhead swivel to 0, 30, and 45 degrees, handling both straight and angular grinding on one machine
Compact footprint compared to larger GL4i variants (100, 150, 200) while retaining the same precision-critical components and spindle technology
Proven Toyoda build quality — forum users consistently report these machines hold tolerances for decades with proper maintenance

Limitations

500 mm between centers limits workpiece length; shops grinding longer shafts will need to step up to the GL4i-100 or larger variants
3.7 kW wheel spindle motor is adequate for production OD grinding but may limit metal removal rates on aggressive roughing operations compared to machines with 7.5 kW+ motors
JTEKT dealer and service network is smaller than Haas or DMG Mori in some North American regions, which can mean longer lead times for field service
No built-in ID grinding capability in the standard configuration — this is a dedicated OD grinder, not a universal ID/OD machine
New machine pricing north of $150K puts it in premium territory; shops on a budget may find used Toyoda GL4P models or competitors more accessible
Wheelhead swivel on the Switch variant is manual (0/30/45 degree positions), not CNC-controlled — changing configurations requires manual adjustment

Best For

Automotive and bearing manufacturers running high-volume OD grinding of shafts, pins, and journals that demand sub-micron repeatability Production grinding shops that need a compact-footprint cylindrical grinder without sacrificing spindle quality or thermal stability Shops grinding hardened steel and superalloy components where spindle accuracy and surface finish consistency are non-negotiable Facilities replacing aging Toyoda GL4P or GL4E grinders that want modern thermal management while keeping the proven STAT BEARING platform Job shops handling mixed straight and angular grinding work using the GL4i-50 Switch variant's manual swivel capability Precision component manufacturers holding tolerances tighter than 0.005 mm (0.0002 in) on ground diameters in production quantities

Frequently Asked Questions

01 What does a JTEKT Toyoda GL4i-50 cost new and used?

New GL4i-50 machines typically run $150,000-$250,000 depending on configuration (plain vs. angular head, standard vs. high-speed spindle, automation options). Used Toyoda GL4-series grinders from the 2010s sell in the $40,000-$80,000 range depending on hours and condition. A rebuilt GL4A-50E through JTEKT's own buy-back program commands a premium but comes with factory-spec restoration and updated controls.

02 What is the TOYODA STAT BEARING and why does it matter?

STAT BEARING is JTEKT's patented spindle technology that combines hydrostatic and hydrodynamic principles into a single hybrid bearing design. It completely eliminates metal-to-metal contact inside the wheel spindle bearing, which means zero bearing wear over the life of the machine. Rotational accuracy is 0.016 microns. In practice, this means the machine grinds to the same precision on day one as it does after 10,000+ hours — you don't chase spindle runout as the bearing wears because the bearing doesn't wear.

03 What's the difference between the GL4i-50 and GL4i-50 Switch?

The standard GL4i-50 comes with a fixed wheelhead position (plain or angular, configured at purchase). The GL4i-50 Switch adds a manually swivelable wheelhead that locks at 0, 30, and 45 degree positions. This lets one machine handle both straight OD grinding and angular grinding (like tapers and shoulders) without dedicating separate machines to each operation. The tradeoff is that switching positions is a manual process, not CNC-controlled.

04 What control does the GL4i-50 use?

The GL4i-50 uses JTEKT's proprietary TOYOPUC-GC70 CNC control, purpose-built for grinding applications. It's not a Fanuc or Siemens platform — it's developed in-house specifically for Toyoda grinders. Operators who've run both generations say it's straightforward for grinding cycles but has a steeper learning curve if you're coming from general-purpose CNC controls.

05 How does the GL4i compare to the older GL4P and GL4E?

The GL4i is the current-generation replacement for the GL4P and GL4E series. Key improvements include the low thermal displacement bed design, heat isolation cover technology, and updated STAT BEARING spindle. The core machine philosophy is the same — production OD grinding with hydrostatic ways and Toyoda's hybrid spindle — but the thermal management package is significantly improved. Many shops running older GL4P machines upgrade to the GL4i when the older machine is due for a major overhaul.

06 Can the GL4i-50 do ID grinding?

No, the GL4i-50 is a dedicated OD cylindrical grinder. If you need combined ID/OD capability on one machine, look at JTEKT's GE-series (like the GE4i-50), which is their universal cylindrical grinder line designed for both internal and external grinding operations. The GL4i trades versatility for optimized OD grinding performance and simpler machine configuration.