Tool clamping collets

Large catalogue and assortment of ER collets made of steel used on all machine tools that use rotating tools (milling machines, CNC milling machines, machining centres, boring machines, drills, screwdrivers) as well as on machine tools where the workpiece is rotated (parallel lathes, automatic lathes, CNC lathes). The ER collet has a very wide range of uses, from joinery to mechanical engineering. ER collets come in different sizes, the number following the ER abbreviation (ER8, ER11, ER16, ER20, ER25, ER32, ER40, ER50) indicates the cone size and the maximum shank diameter that each model can hold.
HOW DOES AN ER COLLET WORK? The function of the ER collet is to clamp the shank of a cylindrical tool, usually a twist drill or milling cutter with a cylindrical shank, during machining. It is mounted inside a chuck whose seat has the same taper as the truncated cone of the ER collet. The chuck also has an external thread on which a ferrule is mounted, which is housed in the specially made seat in the ER collet. When tightening the ring nut, the ER collet is compressed axially, the cuts along the axis of the collet elastically clamp the shank of the twist drill, milling cutter or any tool with a cylindrical shank that is to be machined.

ER collets are available in versions:
- Standard ER normally used for clamping twist drills, milling cutters with cylindrical shanks for which there are no special precision requirements.
- Precise ER collets are ER collets which give us a swing accuracy of approximately 0.005mm for a distance of 2 times the diameter of the closing shank of the twist drill or cylindrical shank cutter.
- Ultra-precision collets are ER collets that provide us with an oscillation accuracy of approx. 0.003 mm for a distance of 2 times the diameter of the closing shank of the twist drill or cylindrical shank cutter.
- Sealed ER are collets that have a rubber seal inserted inside the cuts so that the coolant does not escape from the collet cuts but passes inside the tool. In this case, the tool used normally has holes inside it for the coolant to pass through. 
- ER collets with rigid tapping frame.
- ER collets have the clamping precision of precise collets and also have seals in the collet cuts.

ER collet mounting: The mounting of ER collets is essential to prevent the ER collet from deforming significantly when clamping the tool shank. The use of a torque spanner is therefore recommended in order to ensure a low oscillation error and to avoid damaging the collet and chuck on the surface of the truncated taper part. In addition, the correct closing of the tool ensures correct balancing at high spindle rotations.

Also available are EOP16, EOP25, EOP32 PRT TOOLS brand collets manufactured according to DIN 6388/B and high-precision cylindrical reduction sleeves for clamping tools in hydraulically clamped spindles.

Heavy-duty cylindrical Collets Gaetano Caporali are designed to ensure a secure and stable grip on tools, even under high-speed and high-precision conditions. They are made from high-quality steel and feature contact surface geometry that maximizes friction and reduces the risk of slipping. Their internal mechanism ensures consistent and reliable clamping, even under high loads.