Double Joints – Alloy Steel and Stainless Steel

We stock alloy steel and stainless steel Curtis universal joints in 14 sizes.  Universal 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 Universal Double Joints share the advantages and features of the Curtis single joints:

• Extra angularity allows standard units to operate at angles up to 70°
• Firm, positive lockup of the entire assembly thanks to Curtis’ exclusive Tell-Tale Lock Ring
• Built-in lubrication passages with Curtis’ exclusive internal lubrication system
• Lubrication covers (boots) available in all sizes to retain lubrication and keep out contaminants, extending the life of the joint. Curtis Joints do not require grooves on hubs to retain boots
• Less galling and seizing because Curtis uses dissimilar materials on all bearing surfaces
• Maximum wear and strength from Curtis’ induction hardened forks
• Easy machinability due to Curtis’ soft hubs
• Smooth operations and longer life assured by close and well-controlled tolerances between mating parts and Curtis’ built-in lubrication system
• Perfect concentricity with hubs ground on center and centering holes provided on solid hubs to aid in machining
• Universal joint hub modifications are available, including bores, keyways, set screw holes, cross pin holes, squares, hexes and splines

Alloy Steel Joints

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.

• Alloy steel joints features:
  • 4140-grade steel for all forks. Forks of 7⁄8 inch diameter and larger have induction-hardened bearing areas for strength and durability.
  • Center blocks and pins are machined from 8620 alloy steel and are carburized and case hardened to generate superior wear characteristics

Stainless Steel Joints

Many applications require corrosion resistant universal joints to assure sanitation or to avoid premature oxidation or deterioration. Curtis’ 303 grade stainless steel u-joints are particularly important, for example, to industries that use food processing equipment, and for machinery that comes in contact with corrosive chemicals or is exposed to water for long periods. Furnace applications also benefit from stainless steel, which better withstands high temperatures and other environmental extremes. Curtis stocks 303 stainless in all 14 sizes from 3⁄8″ to 4″. Stainless steel grades 304, 316 and others available by special order.

• Stainless steel joints features:
  • Corrosion-resistant to assure sanitation or to avoid premature oxidation or deterioration
  • 18-8 Type 303 Stainless, non-magnetic steel
  • Dimensionally the same as alloy steel joints, except for OD tolerance

For assistance in ordering your universal joints, please refer to Curtis’ how to order instructions or contact the Curtis sales department for more information.