Custom Made Metric Gears Since 1935

KHK has invested 80 years into the production of metric gears. This dedication to one product has resulted in the sourcing world class equipment and training of personnel in world class production methods. The videos below detail some of the daily activities on the factory floor.

Learn More
Take Virtual Tour
Take Virtual Tour

KHK USA offers 3 Day Factory Direct Shipping

KHK USA offers shipment of over 6,000 stock metric gear products directly from the Japan warehouse to your USA location within 3 business days for a service fee of only US$ 25.00. No freight costs, no customs charges!!! Please contact us at 516-248-3850 today to discuss the details



Kohara Gear introduces new line of Hardened & Ground Hubless Spur Gears

March 7th, 2017 - Kohara Gear has developed a new line of metric hubless spur gears that feature hardened and ground teeth. These gears are produced in Modules 1 thru and feature tooth ranges of 15 to 50 teeth. Made from S45c (AISI 1045 Carbon Steel), the gears are induction hardened to 50-60 HRc on the tooth areas only.

Read About Announcement of New Products - Hardened & Ground Hubless Gear

What is a metric gear?

Traditionally metric means a measurement method based on meter, but when used in sentences as metric gears, it means the sizes of gears are based on the pitch (size) in the unit called module (m).  When the unit of Module is used, the pitch can be computed as the multiple of π.  For example, if the module is 2, the pitch is  6.2832mm, and if the module is 3, the pitch is 9.4248mm.

The module is set to be the unit to indicate the pitch of the gear teeth by ISO, but there are other units such as DP (diametral pitch).  Also, while Module is internationally widely used, DP is still heavily used in the US, but DP can be approximated to Module by the formula, Module = 25.4/DP.

As mentioned before, gears using Module as the unit of Pitch are called Metric Gears, conversely, gears using DP as the unit of Pitch are called Imperial Gears.  The major difference between metric and imperial gearing is in length units, however, while tools such as hobs and shafts, etc. differ in sizes, production processes such as teeth cutting and grinding, manufacturing equipment such as hobbing machines and AISI and SAE specified materials do not fundamentally differ between the two.  While the majority of gear manufacturers in the US make Imperial Gears, KHK's focus is on producing world-class quality metric gearing as its main product offering.