Four-Jaw Shoulder Grip – Chuck Grip for Ø 2 to 250 mm

Four-jaw chuck grip for round and cylindrical specimens

The UGC-VG-030 holds round specimens the way a lathe chuck does: four hardened jaws close on the part from four sides. A two-jaw vise grip touches a cylinder along only two lines, which can flatten tubes or let a smooth bar rotate. Four jaws share the clamping force around the circumference and center the part on the load axis. The grip clamps on the outside diameter, so the specimen does not need a machined shoulder or head. It suits labs testing bars, tubes, housings and assembled cylindrical components, including pull-out tests where a part is held by its body while something is drawn out of it.

Self-centering or independent jaws

Two jaw arrangements are available. In the self-centering version all four jaws move together, so a round specimen is placed on the chuck axis automatically, concentric to within 0.02 to 0.04 mm (0.0008 to 0.0016 in) depending on chuck size. In the independent version each jaw is set on its own, the better choice for castings, out-of-round parts and stepped components. Both use hardened jaw faces with pyramid serration, and special jaws for filter elements and stepped parts can be made.

Chuck sizes

Clamping force and torque below are per jaw and rise with chuck size:

• 80 mm chuck: specimens Ø 2–70 mm, with an extra-long 160 mm coupling

• 100 mm chuck: Ø 2–90 mm, 1.7 kN per jaw, 50 Nm, 0.02 mm concentricity

• 125 mm chuck: Ø 3–125 mm, 2.4 kN per jaw, 75 Nm, 0.03 mm

• 160 mm chuck: Ø 4–160 mm, 3.1 kN per jaw, 120 Nm, 0.03 mm

• 200 mm chuck: Ø 4–200 mm, 3.7 kN per jaw, 160 Nm, 0.04 mm

• 250 mm chuck: Ø 6–250 mm, 4.6 kN (1,034 lbf) per jaw, 180 Nm, 0.04 mm

Typical applications

Round bars and tubes, filter element pull-out tests, cylindrical components and housings, and stepped or irregular parts are the main uses. For filter testing, the chuck grips the filter body while the element or end cap is pulled, giving a direct measure of bond or press-fit strength.

Coupling, capacity and machine fit

The standard coupling is a female clevis for a 15.9 mm (5/8 in) pin; other machine connections are handled with adapters. Maximum tensile load is confirmed on request for the chuck size and specimen, so tell us the force you expect. Smaller chucks pair well with a Galdabini benchtop universal testing machine. If your specimen does have a threaded end or machined head, a shoulder grip or bolt grip may be the simpler fixture.

Give us the specimen diameter range, the jaw arrangement you need and your machine coupling, and we will size the chuck: request a quote.