Hegenscheidt RH 36

Q: What is orbital crankshaft pin grinding?

A crankshaft's pin journals are offset from the main journal centerline (the crankshaft's rotation axis) by the stroke radius. During conventional cylindrical grinding, the crankshaft would need to rotate about the pin journal center — requiring a special orbital chuck that repositions the crankshaft center from main journal to pin journal position. Orbital grinding instead uses a grinding head that tracks the eccentric pin journal position as the crankshaft rotates about its main journal centerline. The grinding head's position is continuously CNC-interpolated to follow the pin journal's orbital path, maintaining contact with the pin journal surface regardless of where the pin is in its eccentric orbit.

Q: What crankshaft diameters does the RH 36 handle?

The RH 36 handles crankshafts with main journal diameters up to 80 mm and pin journal diameters up to 65 mm — covering the full range of passenger car 4-cylinder and 6-cylinder crankshafts, and light commercial vehicle 4-6 cylinder engines. For larger crankshafts (commercial vehicle inline-6 and V8 diesel engines with larger journals), Hegenscheidt offers larger capacity machines in the RH series with main journals up to 120 mm and pin journals up to 100 mm.

Q: How long does it take to grind all pin journals on a 4-cylinder crankshaft?

A 4-cylinder crankshaft has 4 pin journals. On the RH 36 with CBN grinding, all 4 pin journals can be ground in approximately 15-25 seconds per crankshaft — the machine grinds one or two pin journals simultaneously, cycling through all pins in sequence. This production rate enables a single RH 36 to process 150-250 crankshafts per hour, matching the output of a high-volume automotive engine assembly line. This production rate is only achievable with CBN abrasives — conventional abrasive grinding would take 3-5 minutes per crankshaft.

$800,000 - $1,500,000 Updated 2026-03-16

Key Specifications

max crankshaft length

700 mm (27.6 in) for 4-6 cylinder

main journal diameter

Up to 80 mm (3.1 in)

pin journal diameter

Up to 65 mm (2.6 in)

grinding method

CBN belt grinding (orbital) or CBN wheel

cycle time reference

~15-25 sec per crankshaft (4-cylinder)

journal roundness

< 0.003 mm

Overview

The Hegenscheidt RH 36 is a CNC crankshaft pin grinding machine from Hegenscheidt-MFD, the German machine tool specialist in crankshaft and camshaft machining systems for automotive engine manufacturing. Hegenscheidt (based in Erkelenz, Germany, and Mönchengladbach) is one of only two or three companies globally that designs and manufactures complete crankshaft machining lines — from rough turning through finish grinding of main journals and pin journals — at the production rates required by automotive OEM engine assembly.

The RH 36 is Hegenscheidt's crankshaft pin journal grinding machine — specifically designed for the grinding of the eccentric (pin) journal positions of automotive crankshafts. Pin journal grinding differs fundamentally from main journal grinding: while main journals rotate about the crankshaft centerline during grinding, pin journals rotate eccentrically. The RH 36 uses orbital or CBN belt grinding technology to grind pin journals at production rates matching automotive engine assembly line throughput — typically 150-250 crankshafts per hour for passenger car 4-cylinder crankshafts.

Hegenscheidt's RH series crankshaft grinders use CBN (cubic boron nitride) abrasive belts or wheels that can be dressed and changed rapidly to maintain the required journal geometry (diameter, roundness, cylindricity, surface finish Ra 0.2-0.4 µm) across millions of crankshaft cycles. The CBN grinding approach provides significantly longer abrasive life than conventional abrasive stone grinding, reducing wheel changes and maintaining consistent geometry across production runs.

At $800,000-$1,500,000 per machine (crankshaft lines typically consist of multiple machines), the RH 36 is installed at automotive OEM captive crankshaft machining lines and their tier-1 crankshaft suppliers. Major automotive engine producers — General Motors, Ford, Volkswagen, Toyota, and their crankshaft supply base — use Hegenscheidt crankshaft grinding machines as the production standard.

Full Specifications

Parameter	Value
Max Crankshaft Length	700 mm (27.6 in) for 4-6 cylinder
Main Journal Diameter	Up to 80 mm (3.1 in)
Pin Journal Diameter	Up to 65 mm (2.6 in)
Grinding Method	CBN belt grinding (orbital) or CBN wheel
Cycle Time Reference	~15-25 sec per crankshaft (4-cylinder)
Journal Roundness	< 0.003 mm
Surface Finish	Ra 0.2 - 0.4 µm
CNC Control	Siemens Sinumerik 840D sl
Machine Weight	~12,000 kg (26,455 lb)

Strengths & Limitations

Strengths

CBN belt/wheel grinding provides consistent pin journal geometry at automotive production throughputs (150-250 crankshafts/hour)
Orbital pin grinding technology handles eccentric pin journal grinding without complex orbital chucking mechanisms
< 0.003 mm journal roundness matches or exceeds engine assembly crankshaft specification requirements
Hegenscheidt is the global reference for automotive crankshaft machining — installed at virtually all major OEM engine plants
Siemens Sinumerik 840D sl control provides familiar programming environment in European automotive manufacturing

Limitations

$800K-$1.5M per machine, with complete crankshaft lines requiring multiple machines at $5M-$15M+ total investment
Crankshaft grinding expertise is highly specialized — programming, setup, and maintenance require dedicated engineers
CBN belt and wheel costs are significant operating expenses at automotive production volumes
Machine is specific to crankshaft pin journal grinding — not applicable to other applications

Best For

Automotive OEM captive crankshaft machining operations at engine assembly plants producing passenger car and light truck 4-6 cylinder engines Tier-1 crankshaft suppliers producing crankshafts for automotive OEM customers in high production volumes Commercial vehicle engine manufacturers producing crankshafts for diesel truck and bus engines requiring 6-8 cylinder crankshaft grinding Engine remanufacturing operations grinding worn crankshaft pin journals for passenger car and commercial vehicle engine overhaul Performance engine builders requiring precise pin journal geometry for high-performance automotive and motorsport applications

Frequently Asked Questions

01 What is orbital crankshaft pin grinding?

A crankshaft's pin journals are offset from the main journal centerline (the crankshaft's rotation axis) by the stroke radius. During conventional cylindrical grinding, the crankshaft would need to rotate about the pin journal center — requiring a special orbital chuck that repositions the crankshaft center from main journal to pin journal position. Orbital grinding instead uses a grinding head that tracks the eccentric pin journal position as the crankshaft rotates about its main journal centerline. The grinding head's position is continuously CNC-interpolated to follow the pin journal's orbital path, maintaining contact with the pin journal surface regardless of where the pin is in its eccentric orbit.

02 What crankshaft diameters does the RH 36 handle?

The RH 36 handles crankshafts with main journal diameters up to 80 mm and pin journal diameters up to 65 mm — covering the full range of passenger car 4-cylinder and 6-cylinder crankshafts, and light commercial vehicle 4-6 cylinder engines. For larger crankshafts (commercial vehicle inline-6 and V8 diesel engines with larger journals), Hegenscheidt offers larger capacity machines in the RH series with main journals up to 120 mm and pin journals up to 100 mm.

03 How long does it take to grind all pin journals on a 4-cylinder crankshaft?

A 4-cylinder crankshaft has 4 pin journals. On the RH 36 with CBN grinding, all 4 pin journals can be ground in approximately 15-25 seconds per crankshaft — the machine grinds one or two pin journals simultaneously, cycling through all pins in sequence. This production rate enables a single RH 36 to process 150-250 crankshafts per hour, matching the output of a high-volume automotive engine assembly line. This production rate is only achievable with CBN abrasives — conventional abrasive grinding would take 3-5 minutes per crankshaft.