What is the maximum length for a tapped hole in relation to the diameter of the screw?

The maximum length for a tapped hole is generally considered to be 1 1/2 times the diameter of the screw. This guideline helps to ensure that the screw has sufficient grip and engagement within the material, providing optimal strength and preventing issues such as stripping or premature failure of the threaded connection. When the hole is too shallow, it does not allow for adequate threading to hold the screw securely, potentially leading to loosening or breakout.

In practical applications, adhering to the 1 1/2 times diameter rule allows for a balance between sufficient depth for thread engagement and avoiding excessive material removal. This depth allows the threads to cut into the material effectively without compromising the integrity of the surrounding material.

Understanding this standard is crucial for millwrights, as it affects the effectiveness of fastening methods and the overall reliability of mechanical assemblies. Proper calculation of tapped hole length is essential for ensuring structural integrity and the longevity of installations.