Nagel EX 40

$400,000 - $800,000 Updated 2026-03-16

Key Specifications

spindle count

Up to 4 spindles (simultaneous)

bore diameter range

60 - 130 mm (2.4 - 5.1 in)

max bore length

200 mm (7.9 in)

stroke control

Electromechanical (Nagel EMK system)

expansion control

Active (in-process gauging)

surface finish achievable

Ra 0.1 - 1.6 µm

Overview

The Nagel EX 40 is a CNC honing machine from Nagel Maschinen- und Werkzeugfabrik, a German precision machining equipment manufacturer based in Nürtingen that specializes in honing systems for automotive engine, hydraulic, and precision industrial bore manufacturing. Nagel is one of the two primary honing machine manufacturers globally alongside Sunnen (USA) — the Nagel-Sunnen duopoly defines the production honing equipment market for automotive bore finishing.

The EX 40 is Nagel's vertical honing machine for automotive cylinder bore applications — specifically designed for production honing of engine cylinder bores in passenger car and commercial vehicle engines. The machine provides 4-spindle simultaneous honing capability in a vertical configuration, enabling parallel honing of multiple cylinder bores in one cycle — a 4-cylinder block's four bores can be honed simultaneously, significantly reducing cycle time compared to single-spindle sequential honing.

Nagel's EX series machines use their proprietary electromechanical stroke and expansion control system — distinguishing them from hydraulic stroke machines common in the industry. Electromechanical control provides faster stroke reversal, more precise stroke length control, and lower energy consumption than hydraulic actuation. For automotive cylinder bore honing requiring consistent crosshatch angle (45-60°) and precise surface finish (Ra 0.8-1.6 µm for cast iron, Ra 0.4-0.8 µm for aluminum), electromechanical control produces the most consistent results.

At $400,000-$800,000 (depending on spindle count and automation), the EX 40 is installed at automotive engine manufacturing plants as an inline production machine — positioned between cylinder bore machining and engine assembly. Nagel's major customers include the European automotive OEMs and their engine production suppliers.

Full Specifications

Parameter	Value
Spindle Count	Up to 4 spindles (simultaneous)
Bore Diameter Range	60 - 130 mm (2.4 - 5.1 in)
Max Bore Length	200 mm (7.9 in)
Stroke Control	Electromechanical (Nagel EMK system)
Expansion Control	Active (in-process gauging)
Surface Finish Achievable	Ra 0.1 - 1.6 µm
Bore Roundness	< 0.003 mm
Cylindricity	< 0.003 mm per 100 mm
Cycle Time Reference	~30-60 sec (4-cylinder engine block, 4-spindle)
CNC Control	Nagel ProHone CNC
Machine Weight	~8,000 kg (17,637 lb)
Manufacturer	Nordson
Model	BW-200MP
Amperage	75 A

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

Strengths & Limitations

Strengths

4-spindle simultaneous honing completes all cylinder bores in a 4-cylinder engine block in a single 30-60 second cycle
Electromechanical stroke control provides faster reversal and more precise stroke length than hydraulic systems
Active in-process gauging automatically controls bore expansion to reach target diameter with specified finishing behavior
Nagel's ProHone CNC control provides dedicated honing process programming without G-code honing parameter management
Nagel's global service organization and abrasive supply chain supports continuous production line operation

Limitations

$400K-$800K investment requires automotive production volumes to justify — not appropriate for low-volume engine building
4-spindle configuration requires precise fixture design to position all cylinder bores accurately under each spindle
Honing abrasives are bore-specific — changeover between different engine families (different bore sizes) requires abrasive mandrel changes
Automotive engine bore honing requires process engineering expertise — surface finish, crosshatch angle, and bore geometry all interact

Best For

Automotive engine manufacturing plants producing passenger car and light commercial vehicle 4-6 cylinder engine blocks at production rates Engine component manufacturers producing short block assemblies for automotive assembly line supply Engine remanufacturing operations honing worn cylinder bores for automotive engine overhaul at production rates Performance engine builders requiring consistent cylinder bore finish and roundness across multi-cylinder engines Diesel engine manufacturers honing larger cylinder bores (100-130mm) for commercial vehicle engine production

Frequently Asked Questions

01 Why is cylinder bore honing necessary after boring?

Boring (using a single-point boring bar on a machining center or boring machine) produces the cylinder bore to within 0.05-0.1 mm of final size and good roundness, but leaves a relatively rough surface (Ra 1-3 µm) from the boring tool marks. Engine cylinder bores require Ra 0.4-1.6 µm with a specific crosshatch pattern for optimal piston ring seating and oil retention. Honing achieves this final size, surface finish, and crosshatch pattern in a controlled process that boring alone cannot produce. The crosshatch angle (45-60°) is also critical — too steep or too shallow a crosshatch reduces oil retention and increases oil consumption.

02 What is a plateau hone finish?

Plateau honing uses a two-step honing process: first, coarser grit stones remove material and produce the crosshatch pattern; then, a second pass with fine-grit plateau honing stones removes the sharp peaks from the crosshatch pattern, leaving a surface with deep oil-retaining valleys (from the first honing step) and smooth flat plateaus (from the second step). This plateau finish breaks in faster under piston ring contact and produces lower oil consumption than a conventional honed finish. Nagel's EX 40 supports plateau honing through programmable multi-stage honing cycles.

03 How does Nagel compare to Sunnen for automotive cylinder honing?

Nagel and Sunnen are the two dominant production honing machine manufacturers. Nagel has the strongest presence in European automotive OEM production (Volkswagen, BMW, Mercedes-Benz engine plants use Nagel machines extensively). Sunnen has stronger North American market penetration. Technically, Nagel's electromechanical stroke control is a distinguishing feature — most Sunnen production machines use hydraulic stroke actuation. For new automotive engine plant installations in Europe, Nagel is typically the default specification; in North America, Sunnen is equally strong.