Style comparison chart
Shaft collars
They act as a stop to retain equipment on shafts
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Key advantage
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Characteristics
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Available materials/finish
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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 steelMetric – steel, black oxide.Stainless steel |
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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 aluminumMetric – steel, black oxide and bright finish stainless steel |
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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 steelAluminumMetric – steel, black oxide and bright finish stainless steel |
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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 |
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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
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Key advantage
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Characteristics
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Available materials/finish
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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 |
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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 available in inch without keyway. | Inch, metric – steel, black oxide and bright finish stainless steel |
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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 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.