Collet
A collet chuck is a tensioning means to workpieces or tools with high accuracy quickly and positively to span. Collets can be found on machine tools , but also on hand-operated devices such as B. on some awls (e.g. the awl of a setter , which is subject to great wear and tear and has to be replaced more often). Hand- operated milling cutters , small drills and burins can also be fastened with a collet in one movement.
It consists of an externally conical radially slotted sleeve with a round, sometimes square or hexagonal bore of a defined size.
A collet chuck includes a collet holder with an inner taper that matches the collet. It is clamped by tightening a union nut with which the collet is pressed into the inner cone of the collet holder . On some machines, collets with Morse taper can be clamped directly in the quill . Due to the slotting of the collet, the inside of the bore is evenly compressed, whereby the workpiece or tool is held firmly in place. The clamping range of a collet is very small, which means that collets with corresponding dimensions must be kept for different diameters . 6 mm is a common diameter for small tools. Sizes for 0.2 to 34 mm can be found in stores.
The collet holder is made in such a way that it can accommodate different sizes of collets. The collet chuck is either permanently integrated into the work spindle of the machine or as a tool in the tool holder.
Collets clamp bare or machined parts quickly, firmly and centrically. They are suitable for the highest speeds. Sealing collets allow coolant to be fed into the tool.
The simplest permanently mounted collets, mostly made of brass , with 4 slots, can be found on hand drill bits - clamp a square drill - and screwdriver handle for interchangeable blades with 2 protruding bars. Miniature drilling or grinding machines have removable, externally conical collets for different drill shank diameters up to about 3.2 mm.
It is also common to use brass collets for rotary knobs of potentiometers and rotary switches .