What Is a Metal Collar?
A metal collar is a ring-shaped metal component that is fastened to a drive shaft or a shaft, similar to a spacer. It is often secured with a hexagon socket head cap bolt, although some collars are simply inserted onto the shaft without bolting.
The key differences between collars and spacers are:
- Collar: Taller than their diameter and thinner in wall thickness
- Spacer: Taller than their diameter and thicker in wall thickness
Additionally, set collars are sometimes used synonymously with metal collars.
Metal collars come in integral and two-part separate types, chosen based on the application, usability, etc.
Uses of Metal Collars
Metal collars are primarily used to secure components such as bearings, sprockets, pulleys, gears, and shafts against axial movement by fixing them onto the shaft.
Since metal collars can be positioned anywhere along the shaft, they allow for the attachment and adjustable positioning of brackets or plates on the shaft.
They can also be used without bolting to maintain a consistent spacing between parts, based on the collar’s height.
Principles of Metal Collars
Metal collars are easily fastened to shafts using bolts and are available in various types based on their fixing method:
Standard Type
These collars have a precision hole in their inner diameter corresponding to the shaft diameter and are secured with a hexagon socket head cap screw. However, using a hexagon socket bolt for fixing can scratch the shaft.
Slit Type
Slit-type metal collars have a C-shape with a slit. One side of the slit has a tap, and the opposite side has a hole and washer. Tightening a hexagon socket head cap bolt at this location secures the collar to the shaft.
Split (Two-Part) Type
This type of collar is split into two parts, each secured with a hexagon socket head cap screw.
Materials like carbon steel (S45C), stainless steel (SUS304), and aluminum steel (A2017) are used, with aluminum steel often employed for insertion-only applications instead of standard type hexagon socket head cap screw fastening.