Parallel Keys With Counterbores and Tapped Hole

Machine Keys
A key that relies on two side surfaces as working surfaces, and transfers torque by pressing the sides of the key and the keyway.
Guide key, convenient for installation and fixation, disassembly, reusable.

Machine Keys, is a key that relies on two side surfaces as working surfaces and transfers torque by pressing the sides of the key and the keyway.
Machine Keys are divided into three types: standard machine keys, thin machine keys, guiding machine keys.
Standard machine keys have good centering, high positioning accuracy and easy assembly, but they cannot achieve axial fixation of parts on the shaft. They are used for shafts that are high-speed or subjected to impact and variable loads;
Thin machine keys are used for thin-walled structures and places where the transmission torque is small; guiding machine keys are used to fix the keys on the shaft with screws, and are used for occasions where the parts on the shaft donot move much along the shaft.

1) When the keyway is used in conjunction with the machine key, if the clearance is too large, the machine key will not fix completely due to loosening.
2) When the keyway and the machine key are used too tightly, the machine key cannot be installed in the keyway.