A set screw are a small fastener that is used to hold component in place during an assembly. A set screw can fail if a person select a set screw with an incorrect geometry or teh incorrect material. If a set screw is incorrect, the set screw may slip or the hex socket of the set screw may strip.
Stripping a set screw mean the hex socket is damaged so that a tool can no longer turn the set screw. The first step in selecting a set screw is determine the correct size of the set screw. Set screws comes in many different size, and the size of a set screw determines how much force a person can apply to the set screw.
How to Pick and Use Set Screws
Smaller set screws requires precision tools, but larger set screws require more torque. As the diameter of a set screw increase, the size of the hex key required to turn the set screw also increases. If a person use a hex key that is too small for the set screw, the hex key will strip the hex socket of the set screw.
Because the margin for error is small, a person must ensure that the hex key match the set screw size exactly. The second step in selecting a set screw is choosing the correct point type for the set screw. The point type of a set screw determine how the set screw contacts the part that the set screw is holding.
A cone point is a type of set screw point that dig into a material to create a permanent connection. A cone point is useful if a person want to prevent vibration from loosening the set screw, but a cone point is not useful if a person needs to adjust the part later because a cone point will damage the surface of the part. A flat point or an oval point is a type of set screw point that provide contact without damaging the surface of the part.
A cup point is a type of set screw point that is used for general task because a cup point provides a balance of grip and ease of use. A dog point is a type of set screw point that are designed to fit into a pre-cut groove, and a knurled point is a type of set screw point that is used for high-torque applications on soft metals. The third step in selecting a set screw is choosing the correct material for the set screw.
Alloy steel is a common material for a set screw because alloy steel is hard and alloy steel can bite into a shaft without bending. However, alloy steel can corrode if a person use a set screw in environments near the ocean or in food processing plants. Stainless steel is a material that is resistant to corrosion, but stainless steel is often softer than alloy steel.
Because stainless steel is softer than alloy steel, a person cannot apply as much force to a stainless steel set screw as a person can apply to an alloy steel set screw. Brass is a material that is useful for non-sparking or non-magnetic applications, but brass is too soft to be used on a hardened steel shaft. The final step in using a set screw is the installation of the set screw.
A person may think that applying more force will make the set screw more secure, but applying too much force can cause a set screw to snap or cause the threads to strip. A person should use a calibrated torque value to ensure the set screw is tightened to the correct level. A person should clean all surface and align all parts before the person installs the set screw.
If a person follow these steps, the set screw will function correctly and the assembly will remain secure.
