United Grinding (Studer) CNC Grinding Machines

Studer S33

$250,000 - $400,000 Updated 2026-03-11

Key Specifications

X Travel

370 mm (14.6 in)

center height

175 mm (6.9 in)

distance between centers

400 / 650 / 1,000 / 1,600 mm (15.7 / 25.6 / 40.0 / 63.0 in)

max workpiece weight

150 kg (330 lb)

workhead speed range

1 - 1,500 RPM

max grinding wheel diameter

508 mm (20 in)

Overview

The Studer S33 is a CNC universal cylindrical grinding machine built for shops that need the flexibility to grind external, internal, and flat surfaces in a single clamping — without giving up the rigidity and thermal stability that precision grinding demands. With a 175 mm center height, distances between centers from 400 to 1,600 mm, maximum workpiece weight of 150 kg (330 lb), and a turret wheelhead that accommodates two external and one internal grinding spindle, the S33 handles a broad range of cylindrical grinding work from short precision components to long shafts.

The machine base is cast from Studer's proprietary Granitan S103 mineral casting, and this is where the S33's precision story starts. Granitan provides 6-10x better vibration damping than cast iron and superior thermal stability — short-term temperature fluctuations are largely equalized by the material's thermal mass. For a grinding machine where micron-level precision depends on thermal and mechanical stability, this foundation makes a measurable difference in achievable tolerances and surface finishes compared to cast-iron-based alternatives.

The turret wheelhead with 1-degree Hirth coupling enables automatic swiveling between external and internal grinding operations without reclamping. You can configure it with up to two external grinding spindles (max 508 mm wheel diameter, 80 mm width) and one internal grinding spindle, covering most cylindrical grinding operations in a single setup. External grinding wheel speed reaches 3,200 RPM with 8 kW spindle power, which is sufficient for both conventional and CBN wheel applications.

The X-axis stroke of 370 mm and Z-axis travel options from 400 to 1,600 mm (depending on model variant) cover workpieces from small precision components to long shafts. Rapid traverse speeds are 15,000 mm/min in X and 20,000 mm/min in Z, keeping non-grinding time to a minimum. The workhead speed range of 1-1,500 RPM provides the flexibility to match rotational speed to workpiece diameter and material for optimal grinding conditions.

Studer's StuderGRIND software suite handles programming, simulation, and optimization. The software covers cylindrical grinding, form grinding, and thread grinding with integrated dressing cycles — it's a comprehensive package that reduces the skill barrier for complex grinding operations.

Pricing for a new Studer S33 typically falls in the $250,000-$400,000 range depending on center distance configuration, spindle options, and automation. Used machines from 2010-2020 trade between $80,000 and $250,000. The S33 competes with the Kellenberger 100, Junker Jumat, and Okuma GP series in the universal CNC cylindrical grinding segment.

Full Specifications

Parameter	Value
Center Height	175 mm (6.9 in)
Distance Between Centers	400 / 650 / 1,000 / 1,600 mm (15.7 / 25.6 / 40.0 / 63.0 in)
Max Workpiece Weight	150 kg (330 lb)
Workhead Speed Range	1 - 1,500 RPM
Max Grinding Wheel Diameter	508 mm (20 in)
Max Grinding Wheel Width	80 mm (3.15 in)
External Spindle Power	8 kW (10.7 HP)
External Spindle Speed	Up to 3,200 RPM
Wheelhead Configuration	Turret: 2 external + 1 internal spindle
Wheelhead Swivel	Automatic with 1° Hirth coupling
X-Axis Travel	370 mm (14.6 in)
Rapid Traverse X	15,000 mm/min (591 ipm)
Rapid Traverse Z	20,000 mm/min (787 ipm)
Machine Base	Granitan S103 mineral casting
CNC Control	Fanuc 31i with StuderGRIND software
Software	StuderGRIND (cylindrical, form, thread grinding + dressing)

Strengths & Limitations

Strengths

Granitan S103 mineral casting base provides 6-10x better vibration damping and superior thermal stability compared to cast iron — directly improves achievable tolerances
Turret wheelhead with automatic swiveling and 1-degree Hirth coupling enables external, internal, and flat grinding in a single clamping, eliminating reclamping errors
Four center distance options (400-1,600 mm) let shops choose the configuration that matches their workpiece range without paying for unused capacity
StuderGRIND software suite covers cylindrical, form, and thread grinding with integrated dressing cycles — reduces the skill barrier for complex grinding operations
1-1,500 RPM workhead speed range provides full flexibility to optimize rotational speed for any workpiece diameter and material combination
508 mm max wheel diameter accommodates both conventional and CBN wheels for the full range of grinding applications

Limitations

At $250,000-$400,000 new, the S33 is a premium investment — shops doing primarily simple OD grinding may find better value in single-purpose cylindrical grinders
150 kg max workpiece weight limits the machine to small and medium components — shops grinding heavy shafts and rolls need the larger S41 or S51 platforms
175 mm center height means the maximum workpiece diameter is around 350 mm — large-diameter work requires a higher-center machine
Internal grinding spindle is optional — the base machine configuration may not include it, adding cost for shops that need ID grinding capability

Best For

Job shops and contract grinders that need external, internal, and face grinding in one machine to minimize setup changes and maximize flexibility Precision component manufacturers in aerospace, medical, and automotive where Granitan's thermal stability directly enables tighter tolerances Shops grinding shaft-type workpieces from 50 mm to 1,600 mm between centers, including spindles, collets, toolholders, and precision pins Tool and cutter grinding operations where the turret wheelhead's flexibility covers OD, ID, and profile grinding without dedicated single-purpose machines Individual and batch production environments where the StuderGRIND software reduces setup time and programming complexity for varying part types

Frequently Asked Questions

01 What is Granitan S103 and why does it matter?

Granitan S103 is Studer's proprietary mineral casting (polymer concrete) used for the machine base. It provides 6-10x better vibration damping than cast iron, meaning less of the grinding process vibration reaches the workpiece — which directly improves surface finish and roundness. It also has excellent thermal stability, absorbing short-term temperature changes without dimensional shift. For a precision grinding machine, this foundation material is a genuine performance advantage.

02 How does the Studer S33 compare to the S31?

The S31 is the step-up model with a larger 225 mm center height (vs. 175 mm), heavier workpiece capacity up to 250 kg, and larger wheel diameter capability. The S33 is more compact and cost-effective for workpieces that fit within its 175 mm center height. Both share the same Granitan base, turret wheelhead concept, and StuderGRIND software. Choose the S33 for small-to-medium work and the S31 for larger workpieces and heavier grinding operations.

03 What does a used Studer S33 cost?

Used S33 machines from 2010-2020 typically trade between $80,000 and $250,000 depending on age, hours, center distance variant, and spindle configuration. Machines with the internal grinding spindle and longer center distances command the higher end. Studer grinders hold their value well due to the Granitan base's long-term stability — a well-maintained 10-year-old S33 can still grind to original specifications.

04 Can the S33 use CBN grinding wheels?

Yes, the S33 fully supports CBN (cubic boron nitride) grinding wheels. The 8 kW external spindle with speeds up to 3,200 RPM provides adequate power and speed for CBN applications on hardened steel and other materials. CBN wheels offer significantly longer life and can maintain tighter tolerances over longer production runs compared to conventional wheels. The StuderGRIND software includes CBN-specific dressing and grinding cycles.

05 What center distance should I choose?

Studer offers the S33 in 400, 650, 1,000, and 1,600 mm center distance variants. Choose based on your longest typical workpiece: 400 mm for small precision components, 650 mm for medium-length parts and shafts, 1,000 mm for longer shafts and toolholders, and 1,600 mm for long shafts and rolls. The machine price increases with center distance, so don't overbuy capacity you won't use — 650 mm is the most popular variant for general job shop work.