To assure our customers of prompt service, Curtis stocks standard alloy steel u-joints with solid hubs in 14 sizes. Joints 7⁄8” and larger have Curtis’ Take-Apart feature which allows for specialized modifications with no special tooling required. This feature makes it easy for the end user to disassemble the joint, machine component parts and reassemble without damaging the hubs, pins or center block.
Curtis Alloy Steel Joints feature 4140-grade steel for all forks. Forks of 7⁄8 inch diameter and larger have induction-hardened bearing areas for strength and durability. The body (hubs) of the joints remain in an annealed state, which affords free machinability. Center blocks and pins are machined from 8620 alloy steel and are carburized and case hardened to generate superior wear characteristics yet remain ductile, thereby enabling the joint to handle shock loads without experiencing premature failure. Universal joint hub modifications are available per customer specifications, which include but not limited to bores, keyways, set screw holes, cross pin holes, squares, hexes and splines. For assistance in ordering your universal joints, please refer to Curtis’ how to order instructions or contact the Curtis sales department for more information.
Universal Applications
- Stock Car Racers
- Nuclear Installations
- Tractor Attachments
- In-Plant Utility Vehicles
- Grain Augers
Also available in 303 stainless steel.

NOTE #1. Large bearing pin is provided with an oil passage. 1.00" through 4.00" diameter joints are also fitted with a ball spring oil fitting to retain lubricant.
NOTE #2. Curtis standard single universal joints will operate through angles of 35. For applications requiring greater angles, special design can be employed, enabling the joint to operate at angles up to 45.
Catalog Number | Outside Diameter | Total Length | Centerline to End | Static Torque Rating |
Inch Pounds | ||||
A | C | C/2 | ||
CJ641 | 0.375 | 1.750 | 0.875 | 140 |
CJ642 | 0.500 | 2.000 | 1.000 | 425 |
CJ643 | 0.625 | 2.250 | 1.125 | 900 |
CJ644 | 0.750 | 2.688 | 1.344 | 1610 |
CJ645 | 0.875 | 3.000 | 1.500 | 1800 |
CJ646 | 1.000 | 3.375 | 1.688 | 3050 |
CJ647 | 1.125 | 3.500 | 1.750 | 3500 |
CJ648 | 1.250 | 3.750 | 1.875 | 5500 |
CJ650 | 1.500 | 4.250 | 2.125 | 9000 |
CJ651 | 1.750 | 5.000 | 2.500 | 14000 |
CJ652 | 2.000 | 5.438 | 2.719 | 22000 |
CJ653 | 2.500 | 7.000 | 3.500 | 32000 |
CJ654 | 3.000 | 9.000 | 4.500 | 55000 |
CJ655 | 4.000 | 10.625 | 5.313 | 131000 |