Seiki Seisakujyo

Parallel shaft keys (machine keys) explained

Parallel shaft keys explained

Parallel keys are a critical component used to efficiently convey shaft rotation to gears. These items are used in machine tools, automobiles, construction equipment, food machinery, pumps, and more. Parallel shaft keys come in different names depending on the vendor and industry in which they are used. They are variously referred to as parallel shaft keys, machine keys, and shaft keys, but these all refer to the same product.
These items are used in machine tools, automobiles, construction equipment, food machinery, pumps, and more.

Types of parallel shaft key

Key formfactors

Double-sided square key
Double-sided square key
Double-sided round key
Double-sided round key
Single-side round key
Single-side round key

JIS B1301 standard

Key sizes are standardized under JIS. In 1972, the JIS standards were amended, producing major differences in terms of dimensions and tolerance thresholds. This has led to the use of an “old” and “new” set of JIS standards.

The JIS standards define steel parallel shaft keys, sloped/inclined keys, crescent keys, and the keyways for these to be made in B1301.

We maintain a permanent inventory of 10,000 JIS-compliant parallel shaft keys.


The JIS standards call for a tensile strength of 600N/m㎡ or greater. Some clients, however, require heat treatment, carbide materials, or materials that are difficult to machine as a way of achieving greater resilience, and we are equipped to accommodate these materials.

About fixed keys (key materials).

We have key materials available that can be cut out to your preferred length.
The material can be used for a variety of purposes, including manufacturing paralell shaft keys.

fixed keys

(Usage examples)

  • Usable as the base material for parallel shaft keys with measurements outside JIS standards.
  • For parallel shaft key prototype production and testing.
  • As key material stock to rush-manufacture paralell shaft keys in-house in case of emergency.
  • To manufacture jigs, etc. with high-precision keying materials.

Features of Seiki Seisakujyo JIS-compliant parallel shaft keys

Stable and accurate precision of materials

We use precision cold-drawn materials that allow us to ensure quality and minimize variability within lots to the smallest extent.

Abundant stock

We maintain an inventory of 10,000 JIS-compliant items.

Improved corrosion resistance

SUS316 can be used to achieve greater corrosion resistance.

Free sample

We will send you a sample for free.

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