Class A: Solid Steel Expanding Sleeve

This was the first type of arbor and chuck developed by Hydra-Lock. The expanding member is a solid steel sleeve which has these advantages: maximum accuracy -- (Our standard tolerance is .0002" T.I.R.), repeatability to .000030" is possible with certain designs. There are no dirt-collecting slots to cause inaccuracies between part and arbor. Normal expansion of a one inch arbor is .005" with an additional .002" per added inch of diameter, i.e. a 5" arbor could easily expand .015" and perhaps much more depending on its length.

Class B: Split Steel Expanding Sleeve

The essential difference of this type versus class A is that the sleeve is split, thus rendering it less rigid, more flexible and therefore, greater expansion is possible for a given pressure. A one inch arbor of this class can expand .010" and for each additional inch of diameter add .004", i.e., a 5" arbor can expand .026" or more depending on its length.

Class C: Conform-A-Chuck or Conform-A-Arbor

This type uses a special plastic material (Hydra-Fibre). It has good memory, a high coefficient of friction and excellent wear characteristics. It is primarily used for thin-walled parts and has the unique ability to hold an out-of-round part without rounding it up. This class of Hydra-Lock is used for either OD or ID holding. Since the material is a special plastic, high expansions up to .125", depending on size, can be achieved.

For further information on Conform-A-Chuck and Arbors please refer to the Conform-A Products on this web site.

As the originators and developers of hydraulic holding, in our judgement, there is no more precise, concentric or accurate holding method for tool or part, for ID or OD than Hydra-Lock Arbors and Chucks.