the precise, symmetric form and rigid material of the collet provide precise, repeatable radial centering and axial concentricity. the basic mechanism fixes four of the six degrees of kinematic freedom, two locations and two angles. collets may also be fitted to precisely align parts in the axial direction (a fifth degree of freedom) with an adjustable internal stop or by a shoulder stop machined into the internal form. the remaining sixth degree of freedom, namely the rotation of the part in the collet, may be fixed by using square, hexagonal, or other non-circular part geometry.