Please select your spindle type to order Expanding Collets online…

5C, 16C & 3J Internal Expanding Collets, Eccentric Actuated, ID Clamps & Collet Accessories

Mini Collets, -26 &-2
For bore diameters .065″-2″

MiniCollets, & Forborediameters." "

4 Collets
For bore diameters .500″ – 6″

x side

8 Heavy Duty
For bore diameters .750″ – 6″


ROVI Products manufactures a line of internal expanding collets to fit 5C, 3J and 16C spindles, capable of holding on bores ranging anywhere from .065″ to 6″ in diameter. Our system is composed of three parts: a hardened and ground sleeve to insure accuracy; a rod assembly which consists of the threaded pull rod, 5C collet nut, lock nut and expanding screw, and the machinable expanding collet. Unlike other designs, our expanding collets have a taper on the shank that locks into the sleeve creating a very rigid collet which in turn gives you better concentricity. All ROVI collets are machinable and completely consumable (.0005″ TIR is easily held on production runs and holding .0002 TIR is not uncommon). ROVI collets save time, labor and cost because they can be re-machined for many different jobs. When the collet has been consumed or needs to be replaced, simply remove the existing collet from the sleeve and insert the new collet. It is not necessary to purchase the sleeve and rod assembly for every new collet as other manufacturers may require.

The ROVI mini collet is a unique design which allows this collet to hold on bore diameters from.250″ – .065″. The mini collet is available in three different chucking lengths: 1/4″, 9/16″, and 3/4″, all with a diameter of 7/16″. In addition, a shoulder on the major diameter of this collet allows use of a turning ring for ease of machining.

Our heavy duty collet line for 16C and 3J spindles is capable of holding on bores of.750″ – 6″ in diameter.

We also manufacture special collets to your specifications. Please do not hesitate to call us with any questions you may have. ROVI has been in business since 1965 and we are very proficient in the workholding field.

For those big jobs, we have a line of Heavy Duty Expanding Collets that provide greater strength and rigidity. This collet system is designed to work with machines that have either a 16C or 3J spindle. This system works off the same principle as that of the ROVI 5C system. It still includes the rod assembly, sleeve, and machinable collet. The difference is the larger size. Instead of a 1/4-28 screw, this system uses a 3/8 screw.

With this size screw, you will not have the breakage problem due to excessive hydraulic pressure on the draw tube. Also, the taper on the collet is much bigger than the 5C, thus making a stronger and more rigid expanding collet.


Watch Video Tutorials For Assembling and Machining Expanding Collets here…..

Expanding Collet Assembly

Expanding Collet Machining Part 1

Expanding Collet Machining Part 2

Please select your spindle type to order Expanding Collets online…