Expanding mandrel
Tork-Lok ITW Workholding

The N.A. Woodworth Tork-Lok collet line offers flexibility and affordability, with much of the product available from stock. The Tork-Lok Arbor locates straight and tapered holes on true center within .0005 T.I.R. These arbors feature patented inclined flats that provide full arbor / collet contact throughout the range of operation for highest accuracy and torque transmission. Features include:

Flat surfaces are in constant contact on both expansion and contraction, providing higher accuracy.
Precision mated flats provide for greater torque transmission
Built in safety stops control both expansion and contractions, thereby reducing collet breakage
Metal to metal contact excludes foreign matter which in turn reduces wear and assures accuracy
Preload features assures easy part removal