of the above traits, scroll chucks offer always № 1 and № 2; usually № 3; to varying extents № 4 (depending on the situation); but not reliably № 5. independent-jaw chucks offer always № 3; usually № 4; reliably № 5 (but at the expense of paying a skilled user to spend time achieving it); never № 2; and generally not № 1. meanwhile, a collet chuck can deliver all reliably, and with no need for a skilled user (№s 3 to 5 do depend on the object being clamped closely matching the size and shape of the collet's clamping surface. this constraint is usually not a problem when the object is good-quality bar stock; the shank of a well maintained drill bit, reamer, end mill, etc.; or a previously machined part that is being rechucked for additional cutting operations).