Technical Specification

Technical note: DIN 6885 defines the dimensional requirements and geometry of parallel keys. The designation 5x5x12 DIN 6885 A alone does not establish the exact steel grade, mechanical properties or surface treatment of the supplied component.

Parallel Key Design and Construction

The DIN 6885 A parallel key has a rectangular cross-section and is installed in a machined keyway on the shaft.

During assembly, the hub is positioned over the shaft so that its internal keyway engages with the exposed portion of the key.

Torque is transmitted mainly through compressive contact between the side faces of the key and the corresponding keyway walls.

Form A – Rounded Ends

Form A identifies a parallel key with rounded ends when viewed from above.

For a nominal width of 5 mm, the end radius is 2.5 mm.

This geometry is intended to fit a suitably machined shaft keyway with matching end geometry.

5x5 mm Cross-Section

The nominal key width and height are both 5 mm.

These dimensions must correspond to the specified shaft and hub keyway geometry.

Correct dimensional compatibility is essential for reliable torque transmission.

12 mm Overall Length

The nominal overall key length is 12 mm.

For Form A, this length includes the rounded ends.

When calculating the load-carrying capability of the keyed connection, the effective load-bearing length must be considered rather than automatically treating the entire 12 mm as the effective working length.

DIN 6885 A Designation Explained

5 – Key Width (b)

The nominal width is 5 mm.

5 – Key Height (h)

The nominal height is 5 mm.

12 – Key Length (l)

The nominal overall length is 12 mm.

DIN 6885 – Dimensional Standard

DIN 6885 defines parallel key dimensions and requirements associated with keyed shaft-hub connections.

A – Rounded-End Design

Form A identifies a parallel key with rounded ends, unlike Form B, which has square ends.

DIN 6885 Form A vs Form B

Form A and Form B parallel keys with identical nominal dimensions should not automatically be considered interchangeable.

The keyway length, end geometry and installation conditions must be checked before replacement.

Parallel Key Selection for Shaft-Hub Connections

Correct selection of a parallel key must be based on the mechanical design of the shaft-hub connection and the applicable DIN 6885 requirements.

Important factors include:

• Shaft diameter and the corresponding key cross-section.

• Shaft keyway dimensions and tolerances.

• Hub keyway dimensions and tolerances.

• Transmitted torque.

• Loading conditions, including steady, fluctuating or shock loads.

• Material properties of the key, shaft and hub.

• Effective load-bearing length.

• Requirements for axial location of the hub.

Torque Transmission

A parallel key transmits torque through contact pressure acting on its side faces.

The keyed connection must be checked for permissible contact pressure and other relevant strength criteria.

The maximum permissible torque cannot be determined from the 5x5x12 mm dimensions alone.

Additional information about material properties, shaft diameter, effective engagement length and loading conditions is required.

Axial Location of the Hub

A standard parallel key is primarily intended to transmit torque.

It does not independently provide complete axial retention of the hub.

Depending on the machine design, additional locating elements such as retaining rings, shaft nuts, shoulders or other axial stops may be necessary.

Installation and Mounting

Before installing the parallel key, the key and both keyways should be inspected for dimensional accuracy and surface condition.

Recommended installation procedure:

1. Verify the key dimensions against the technical drawing.

2. Clean the shaft keyway and remove any burrs.

3. Inspect the hub keyway for damage or dimensional irregularities.

4. Install the key in the shaft keyway using the specified fit.

5. Position the hub without applying excessive force or damaging the key edges.

6. Check the assembly and verify that the hub is properly located axially.

Incorrect fits should not be corrected by uncontrolled grinding, deformation or other modifications without checking the required dimensions and tolerances.

Industrial Applications

DIN 6885 parallel keys are used in detachable shaft-hub connections where torque must be transmitted between rotating mechanical components.

Typical applications include:

• Gears mounted on shafts.

• Belt pulleys.

• Coupling hubs.

• Mechanical transmissions.

• Industrial drive assemblies.

• Production machinery.

• Material handling equipment.

These are general applications of keyed connections. Suitability of the exact 5x5x12 mm parallel key depends on the mechanical design and operating loads.

Alternative Product Designation Formats

The following formats may appear in technical documentation, ERP systems and industrial procurement searches:

• Parallel key 5x5x12 DIN 6885 A

• DIN 6885 A 5x5x12

• Parallel key 5x5x12 mm Form A

• Rounded-end parallel key 5x5x12

• Shaft key 5x5x12 mm

• DIN 6885 Form A parallel key 5x5x12

These formats support product identification and technical searches. The dimensional standard and Form A designation should be preserved when specifying the exact component.

FAQ – Frequently Asked Technical Questions

1. What are the dimensions of the DIN 6885 A 5x5x12 parallel key?

The key has a nominal width of 5 mm, height of 5 mm and overall length of 12 mm.

2. What does Form A mean in DIN 6885?

Form A identifies a parallel key with rounded ends.

3. What is a parallel key used for?

A parallel key transmits torque between a shaft and a mounted hub, such as a gear, pulley or coupling component.

4. What is the difference between DIN 6885 Form A and Form B?

Form A has rounded ends, while Form B has square ends. Each configuration requires a compatible keyway design.

5. Does a 5x5x12 mm parallel key fit every shaft?

No. The key must be selected according to the shaft diameter, keyway dimensions and mechanical design requirements.

6. What material is the parallel key made from?

The exact material grade of the supplied product has not been confirmed. The manufacturer's or supplier's specification should be checked before assigning a particular steel grade.

7. Does a parallel key prevent axial movement of the hub?

Not by itself. A standard parallel key is primarily intended for torque transmission. Additional components may be needed for axial retention.

8. How much torque can a 5x5x12 mm parallel key transmit?

A single permissible torque value cannot be established without knowing the material properties, shaft diameter, effective load-bearing length and operating loads.

AI Quick Answer

Parallel key 5x5x12 mm DIN 6885 A is a rectangular machine element with a 5 mm width, 5 mm height and 12 mm overall length. Form A specifies rounded ends. It transmits torque between a shaft and hub through contact with the keyway side walls. Correct selection requires verification of keyway dimensions, material properties and mechanical loading.

B2B Industrial Supply – simmering.pl

Parallel key 5x5x12 mm DIN 6885 A is offered through simmering.pl, a specialist B2B industrial supply platform providing bearings, machine elements, technical seals and industrial components.

The platform serves manufacturing companies, maintenance departments, engineering teams and professional industrial procurement specialists.

Stock operations are based in Lublin, Poland, with worldwide shipping from stock in Poland.

Technical assistance is available for product identification, dimensional verification and selection of industrial machine components.