Machine Parts

Strap Clamp: The simpliest and probably most commonly used clamp is the strap clamp.All strap clamps employ the principles of levers.The most important feature is that the clamping bar can be slid onto and off of the workpiece for easy workpiece removal.A compression spring between the base clamping bar holds the bar in position when the clamp bar is loosened. The pillar and heel pin, rests in a groove on the under side of the bar to prevent it from turning when the clamping bar is loosen .                                             Advantages of Strap Clamp: The talked of topics of the merits of this type of clamp are stated below- Ø The design of the strap clamp is the simpliest one. Ø If the height of the workpiece varies, strap clamp can hold it without any problem. Ø Strap clamping may be actuated by hand knob. Ø There is no effect of vibration like other type of clamp. Ø It is easy to load and unload within the clamp.

                                                          The additional considerations applied to the lathe fixtures are given below: 1. Clamps and other holding devices should be designed in such a way that they will not be loosened by centrifugal force. 2. The workpiece should be gripped on its largest diameter,and whenever possible the gripping diameter should be larger than the diameter being machined. 3. The fixture should be well balanced.Irregular –shaped workpieces may have to be counter weighted to prevent vibration .It is not necessary to achieve perfect balance unless the workpiece is rotating at high speeds. 4. The fixtures should be as lightweight as possible since it is rotating. 5. projections and sharp corners should be avoided as the operator may not be able to see them while the tool is rotating. 6. Thin sections of the workpiece may require support to resist the pressure of the lathe tool