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Gun Drilling Unions

Talco, Inc. takes pride in the machining and assembly of High Capacity Gun Drilling Unions, to handle high-pressure coolant and provide dynamic sealing for demanding applications.

Gun drilling coolant unions are a special type of rotary union (also known as “rotary joint”) designed to deliver heat transfer or cooling fluid directly to the center of the tool, where it is needed to prevent overheating and breakage of the gun drill.

Talco’s gun drilling unions feature a passage size of over one-half inch, which provides a high fluid handling capacity to the rotary joint (sometimes also called a “swivel joint”). Our gun drilling unions also feature balanced sintered silicon carbide face seals. These high quality and durable balanced seals use external spring pressure to maintain a positive seal within the gun drilling union or joint. The operating pressure of the coolant will not affect the seal load. The gun drilling union is supported by ABEC 1 Radial Contact Ball Bearings. Our gun drilling union or joint also features a nickel-plated steel shaft and an aluminum housing.

Talco’s high capacity gun drilling unions operate with a maximum hydraulic pressure of 1500 PSI (100 bar), a maximum temperature of 250 degrees Fahrenheit (120 degrees Centigrade), and a maximum speed of 5000 RPM.

Talco is also happy to do custom work. We specialize in adapting our products to fit your machines, temperature ranges and pressure requirements. We can manufacture rotary unions in stainless steel, aluminum and carbon steel. Contact our engineering department with your needs.

Gun Drilling Unions

Recommended Operating Specifications

American Units:
Metric Units:
Max. Hydraulic Pressure 1500 PSI
Max. Hydraulic Pressure 100 bar
Max. Temperature 250 deg. F
Max. Temperature 120 deg. C
Max Speed 5000 RPM
Max Speed 5000 RPM


  • Over 1/2" Diameter Passage Size
  • Balanced Sintered Silicon Carbide Face Seals
  • ABEC 1 Radial Contact Ball Bearings
  • Nickel Plated Steel Shaft & Aluminum Housing

Gun Drilling Unions

High Capacity Gun Drilling Union
Model A B C D E F G H I J L
A-77000 7/8"-18 UNF (left handed) 7/8"-14 UNC (#10 SAE) 2.5" 5.74" 2 .00" 1.00" .56" 1.50" 1.0000" .50 1.50

Questions? Comments? Please contact us!

Talco Inc. Rotary Union - Quality Craftsmanship for Greater ReliabilityCall Toll Free: 800-776-4896