Screwed mandrel This mandrel is threaded at one end and has a collar. It is used to hold workpieces having threaded holes. Step mandrel Step mandrel has step of different sizes of holes. Collar mandrel This mandrel has two collars. Collars fit firmly into the hole of workpiece. Collar mandrel is lighter in weight. It is used for holding workpieces having larger diameter holes. MILLING FIXTURE Location – Machine Table Use – For Clamping Workpiece Should be Strong and Rigid Clearance should be provided for disposal of swarf Elements of Milling Fixture Base Tenon Strip Setting Block T – Bolts Clamping Device Locating and Positioning element Base Thickness 20-25mm Should be Rigid, absorb cutting forces Material used – Cast Iron Tenon Strip Locate fixture base with reference to milling cutter Fixes the base of the fixture to machine table in same relative position every time Material used – hardened and ground steel Setting block With the help of Feeler gauge(used to check positional accuracy) Use – reduces time for setting milling cutter relative to fixture Material used – hardened and ground steel T – bolts Use – binds fixture to mill table Clamping Device Should be rigid Must not loosen by vibration caused during cutting Must not interfere during cutting operation Locating and positioning element Cylindrical locating pins, diamond locators Different types of milling Single Piece Milling String Milling Reciprocal Milling Progressive Milling Index Milling Rotary Milling Dimensional Data of Milling Dimensions of Milling Machine table Dimensions of T – Slots Center to Center distance of T – Slots Length of Travel in all three fed directions Strap Clamps Used for holding the fixture bases(fixture to be used on more than one machine) Should be extremely rigid Should be tight even during more vibrations.