Style comparison chart
Shaft collars
They act as a stop to retain equipment on shafts
Key advantage |
Characteristics |
Available
materials/finish |
|
|
Set |
Most economical shaft collar. |
You install them on a 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 |
Don'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. Function 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 |
Come as single and double split. Have recessed screw heads. |
Inch -steel black oxide and bright finish stainless steel |
|
Threaded |
Split collars that 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 Double – steel, black oxide |
Shaft couplings
They connect two shafts such as a temporary repair when a shaft breaks, or as a permanent connector between a power source and a component driven on a separate shaft
Key
advantage |
Characteristics |
Available
materials/finish |
|
Rigid |
Most economical. Come with or without keyways. Held by two set screws. |
Install by a set screw that extends through the shaft collar. Unfortunately, the screw often mars the shaft. |
Inch - steel, black oxide |
Single split |
Come with or without keyways. |
Come with straight and stepped bores (inch only) for joining different diameter shafts. Clamp with four cap screws. Stepped bores available in inch without keyway. |
Inch, metric - steel, black oxide and bright finish stainless steel |
Double split |
Come 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 single split. Double split with keyway provide the greatest load available in a coupling application. Stepped bores available with and without keyways in inch. |
Inch, metric - steel, black oxide and bright finish stainless steel |
More on shaft collars and couplings
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.
