Collars and Couplings Style Comparison Chart

Tips on Comparing Different Types of Collars and Couplings 

Additional Information on Material Content and Finishes

Material content

  • Steel is mild low carbon to ASTM A 283 GrC or equivalent, which can be machined, welded, and case hardened.
  • Stainless steel is 18-8 series, passivated.
  • Aluminum is aircraft Grade 2024A or equivalent, which has high strength, excellent fatigue resistance, and a bright finish.

Finishes

  • Standard finishes on steel collars are RoHS-compliant bright zinc and clear chromate or black oxide and oil.
  • Custom finishes such as chrome, nickel, zinc, and yellow dichromate are also available on steel split collars and couplings.

Note: Plated shaft collars and couplings come with unplated screws. This is to protect against hydrogen embrittlement, which causes failures when hardened socket cap screws are plated.

Shaft Collars Comparison Chart

 

Type Key Advantage Characteristics Available Materials and Finish
Set Most economical shaft collar

Install on the shaft by tightening a set screw that extends through the shaft collar.

Unfortunately, the screw often mars the shaft.

 

Inch – steel, zinc plated, black oxide, plain and bright finish. Stainless steel

Metric – steel, black oxide. Stainless steel

Single split Doesn’t mar the shaft and provides a much greater axial load than set screw collars.

Used when the end of the shaft is accessible, and collars can be slid into position. Functions as a clamp around the circumference of the shaft.

Held in place by one socket head cap screw. Diameters up to 1-1/2 inches (35mm) have a relief cut, which allows the smaller screws used in those diameters to provide maximum clamping load.

 

Inch – steel, black oxide, bright finish stainless steel, and aluminum

Metric – steel, black oxide, and bright finish stainless steel

Double split Loaded values exceed that of a single split collar by about 10%.

Used for mid-shaft applications when components such as bearings, sprockets, or sheaves are already in place, or when a slightly greater axial load is desired.

Can compensate for a slightly undersized or oversized shaft. Held in place by two socket head cap screws.

Inch -steel, black oxide, and bright finish stainless steel, aluminum

Metric – steel, black oxide, and bright finish stainless steel

Heavy split Slightly larger outer diameter than standard split collars Comes as single and double split. Have recessed screw heads.

Inch -steel black oxide and bright finish stainless steel

 

Threaded Split collars are used on threaded shafts. Available in USS (coarse) and SAE (fine) thread. Single and double split styles.

Inch - Single – steel black oxide, bright finish stainless steel

Inch - Double – steel, black oxide

 

Shaft Couplings Comparison Chart

 

Type Key Advantage Characteristics Available Materials and Finish
Rigid Most economical. Comes with or without keyways. Held by two set screws.

Installed by a set screw that extends through the shaft collar. Unfortunately, that screw often mars the shaft.

Inch – steel, black oxide

Single split Comes with or without keyways.

Come with straight and stepped bores (inch only) for joining different diameter shafts. Clamp with four cap screws. Stepped bores are available in inch without a keyway.

Inch – steel, black oxide, and bright finish stainless steel

Metric – steel, black oxide, and bright finish stainless steel

Double split Comes with or without keyways.

Come with straight and stepped bores (inch only) for joining different diameter shafts. Develop a greater load than a single split shaft coupling, due to the eight-socket cap screws vs. the four used in a single split.

Double split with keyway provides the greatest load available in a coupling application. Stepped bores are available with and without keyways in inch.

Inch - steel, black oxide, and bright finish stainless steel. Aluminum

Metric – steel, black oxide. and bright finish stainless steel

 

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