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Types de mandrin

Various types of drill chucks or clamping devices are needed to hold application tools such as twist drill bits, reamers, countersinks, de-burrers and the like.

Key-type chuck
The geared chuck or key-type chuck is the most common type found on drills. Typical for this chuck type are the visible rotary gears which, with the help of an open-toothed chuck key, open and close the three gripping jaws. This is accomplished by the internal toothing of the crown gear and the external toothing of the gripping jaws. Three power transmissions ensure that the application tools have a firm seat:

- the manual force applied to the lever length of the chuck key which tightens the connection,

- the transmission ratio from the number of teeth on the geared key to the number of teeth on the crown gear,

- the transmission ratio from the internal crown gear thread to the gripping jaw thread.

Standard drill chucks have a chucking capacity of

0.5?10mm 1.5?13mm 3.0?16mm with the connecting threads 3/8"?24 UNF 1/2"?20 UNF 5/8"?16 UNF  5/8"?16 UNF


Keyless chuck
The keyless chuck is recommended for applications which require fast and frequent bit switching. The chuck can be recognised by its corded turning sleeve, and there is no chuck key required. The gripping jaws are operated by restricted guidance through the jaw cage which slides the jaws back or forth when you turn the rotary sleeve. In contrast to geared chucks, drill shanks are clamped here on a greater length, and the pressure applied during drilling further increases the gripping force. No chuck key is required to open or close the gripping jaws, manual force is quite sufficient. A distinction must be made between keyless chucks

a) for rotation-only clockwise operation

b) for hammer/rotation clockwise operation

c) for rotation-only reversible operation

d) for hammer/rotation reversible operation

For the versions b, c, d you often need an additional locking mechanism ? also called a gripping power safety lock ?. Standard chucking capacities are:

1.5?10 mm 1,0?13 mm 3.0?16 mm with connecting threads

1/2"?20 UNF 1/2"?20 UNF 5/8"?16 UNF

Two-jaw chuck
Two-jaw chucks are special chucks for square shanks which you find, for example, on taps. The gripping jaws are tightened like geared chucks from the outside, however with a square key or spanner over a threaded spindle with opposite thread. Many two-jaw chucks are equipped with a cardan suspension to compensate for the imprecision of the guiding hand.

Crown gear chuck with gripping power safety lock
During rotation/hammer applications in stone the clamped bit may work itself loose due to the percussive force. The tensile lock or gripping power safety lock has the effect of locking the tightened jaws in their locked position.

Special versions of these four different types of drill chucks are still being manufactured which recognise their diverse applications.

Geared chucks with SDS-plus drive shaft for light rotary hammers for work with commercially available carbide-tipped and twist drill bits.

Geared chuck with small spline drive shaft for drilling with impact.

Geared chuck with large spline drive shaft for drilling with impact.

Small and micro drills also use collets to mount twist drill bits.