A Parallel key is a connecting element that transmits torque. It is an elongated component, usually made of metal, that sits between two parts like a “driver” – for example, between a shaft (round, rotating) and a hub (e.g., a gear wheel or a belt pulley).
Its function:
– It ensures that the shaft and hub are firmly connected to each other.
– It transmits the torque from the shaft to the component without slipping.
– At the same time, it can be easily removed again if necessary (unlike a permanent weld).
– It can also serve as a predetermined breaking point. This means that the key should break before the shaft or gear wheel breaks.

Parallel keys usually have standardized dimensions and tolerances, i.e., the permissible deviations from the exact nominal size.
These are specified in DIN 6885 (Part 1 for parallel keys).
Simply explained:
– Width of the key → usually h9
– Height of the key → often h11 (except for square keys)
– Length of the key → is in the negative range Example: for a length of 40 mm, the key has -0.2 mm

🔍 Example:
A parallel key with a width of 10 mm (h9) has a negative tolerance, e.g., 10.00 – 9.964 mm. If the shaft groove width for the parallel key has a P9 tolerance, the parallel key would have a tight fit. With a groove with an N9 tolerance, the parallel key would have a slight fit.

A Parallel key is a connecting element.

DIN parallel keys are milled/sawn from cold-rolled steel with a tolerance of h9/h11 and then trowalized (deburred and edges rounded in accordance with standards).
They are then cleaned and packaged in packaging systems according to specifications or units.

Parallel keys are subject to torsion (torque). Signs of wear may appear over time, but this can be counteracted in advance by means of refinement (e.g., heat treatment).
There are also other options available. Please feel free to ask us for more information.

A wedge is driven into the groove, thereby achieving a higher form fit. It is used when there is higher wear, e.g., the groove of the shaft becomes worn out over time.
The wedge can then be easily replaced from the outside. Nowadays, however, wedges are rarely used due to manufacturing tolerances.

There are three shapes. Shape A = both ends are rounded; Shape B = both ends are straight; Shape AB = one end is straight, one end is rounded.

Advantages:
– Standardized components (defined standards, standardized processes)
– Cost-effective due to series production
– Manufactured from standard materials
– Economical solution for power/torque transmission
– Easy to replace, allowing the shaft and hub to be separated again
Disadvantages:
– The shaft is weakened by the milling for the parallel keyway
– Over time, play can develop due to the constant alternating load

It works by form fit, by being pressed in. It transmits torque from a shaft to a hub (e.g., gear, coupling, pulley) by inserting a parallel key into the grooves of the shaft and hub.

This always depends on the dimensions, size, tolerance, material, strength, and surface treatment. The order quantity also has an impact on the price.

Woodruff keys are mainly used in tapered connections. An example of this is steering wheels on steering columns: here, a tapered seat is used for centering, and the woodruff key prevents twisting.

Yes – we specialize in custom solutions, including for parallel keys. Feel free to ask us!
For example, we have already modified many standard parallel keys in the automotive industry to meet specific design requirements – reliably and cost-effectively.

Firstly, we are a series manufacturer and produce from stocked, close-tolerance raw materials.
This means an excellent end product that fully meets the standard-specific requirements, and the stock levels ensure high availability.
A specific nosta manufacturing process also ensures absolutely perfect installability, thus saving time and money during installation.

Form A = rounded ends on both sides
Form B = straight ends on both sides
Form AB = one end straight, one end rounded
Form AS = Form A with release thread
These are the standard forms. These are also available drilled in versions C, D, E, F.