Operation for O.D. Location of Part

Hydraulic chucks operate by a displacement principle and by contracting metals within their elastic limits. This contaction is achieved by hydraulic pressure, a true, accurate, and equalized centering force.

By turning the actuating screw, the piston forces the fluid from the reservoir through the ports down and around the sleeve. The fluid contracts the steel sleeve around the outside diameter of the part. The part is held by the pressure of this contraction force and locates the true centerline of the part.

Amount of Contraction

Expansion is approximately 0.003" for the first inch of diameter.

Add 0.002 inch expansion for each additional inch of diameter.

Greater expansion can be obtained under certain design conditions. Our engineering staff will assist you on all designs.


0.0002 T.I.R. is normal for Jerry Tools.

Closer tolerances can be held if required.

Minimum/Maximum Size

Minimum chuck size - 0.187" diameter

Maximum arbor size - 48"