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Page Thumb U-Joints ISC CompaniesUniversal Joints (U-Joints)

ISC Companies and affiliate Adams-ISC are distributors of mechanical power transmission parts including Universal Joints (U-Joints). For more information about the brands we offer and/or pricing, please contact us by phone 763-559-0033, by email [email protected], or by filling out our online contact form.

Mechanically flexible U-Joints accommodate end movement by using a telescoping shaft (square shafting or splines). U-Joints function by a sliding motion between two flanges that are fork-shaped (a yoke) and having a hole (eye) radially through the eye that is connected by a cross. They allow larger angles than flexible couplings and are used in applications where high misalignment needs to be accommodated (1 to 30 degrees).

U-joints are available with two hub styles; solid and bored. Solid hubs do not have a machined hole. Bored hubs have a hole and are named for the hole shape; round, hex, or square style. Two bored styles that deviate from these common shapes are splined, which have longitudinal grooves inside the bore; and keyed, which have keyways to prevent rotation of the U-joint on the shaft.

There are many varieties of U-Joints, some of which are very complex. The simplest category called Cardan U-Joints, are either block-and-pin or bearing-and-cross types.

Common Cardan U-Joint Types

Block-and-Pin U-Joints

Available in both single and double configurations. A single U-Joint has two shafts with u-shaped and drilled ends, a center block, and two pins that secure the block. Vibrations, caused by velocity changes, limits this type to very low speeds. A double U-Joint has a center piece connected on each end with separate joints.


A single U-Joint compensates for angular misalignment, and a double can handle angular and parallel misalignment. If changes in misalignment or shaft end movement occur, a telescoping splined shaft provides the necessary adjustment in shaft length.

Cross and Bearing U-Joint PictureBearing-and-Cross U-Joints

Two u-shaped hubs are joined by a cross-shaped piece. Needle bearings at each end of the cross-shaped piece fit into the hub arms. They are torsionally rigid and capable of up 15 degrees of angular misalignment.

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PTDA-Handbook-CoverContent on this page was created using excerpts from the Power Transmission Handbook (5th Edition), which is written and sold by the Power Transmission Distributor’s Association (PTDA).

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ISC Companies and affiliate Adams-ISC are industrial distributors of bearings and mechanical power transmission parts. We have many different models and brands in stock for fast delivery. Our sales professionals are happy to assist you in the selection process to ensure the correct part is specified for your application. Get a quote by clicking below on “Request Pricing” and filling out the contact form or give us a call at 1-800-627-9434.

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