Ever wonder how machine element which rotates with shafts, how are they joined? Well, there are many ways, but one of the most effective and easy way is to use a key. A key is a machine element used to connect a rotating machine element to a shaft. The key prevents relative rotation between the two parts and enables torque transmission.A key is used for temporary fastening. For a key to function, the shaft and rotating machine element must have a keyway, also known as a keyseat, which is a slot or pocket the key fits in. The whole system is called a keyed joint.They are used in many components like pulleys, clutches, gears etc. Like, most of machine elements, they are also of many kinds. I will here discuss the simple type of Keyways. You can use your Pro/E's, Solidwork's etc to design them in modelling and apply standard tolerances during drafting. Below is the picture of designing a simple standard key for a shaft.For the bores and for other kinds of keyed joints, you can look for over internet or various design books.
Machining: They are generally machined on shafts by using milling machines. The rotating tool of vertical mill removes metal from the surface of shaft.In the shafts they look like this.
Machining of square keyways in bore of shafts, gear, or pulleys etc is done by machine called slot machine. It uses a tool in the form of bit of HSS material, which can be grinded to desired dimensions to machine desired keyways in the bore. The tool moves up and down and machines the Keyway. Below are the photos of slot machine and its keyway tool.
The large Keyway being made in the bore of large spiral bevel gear of 5 module by slot machine.
