Supplied with :
ER clamping nut.

Optional extras :
ER collets No. 308881 − 309434, ER chuck keys No. 309680 – 309720 or 613300, ER clamping nut 309610. Pull studs (PS) No. 308760 − 308806. Pull stud wrenches No. 308820; 308835.

Application :
For clamping tools with parallel shank in collets to DIN 6499 Form A and B.

Note :
Matching clamping nut No. 309580 or 309610.

Version :
Taper ground internally and externally. All shanks hard turned (for smooth running!). With RFID/Balluffchip bore. High-quality precision clamping nut.Clamping nut balanced for HSM (G2.5/25,000 rpm).Optimum wear characteristics and torque transmission due to the coated precision clamping nut.

Advantage :
The double contact between the taper and the flat flange creates a more stable and precise clamping situation:Better surface qualityLonger tool life timesConsistent seating in the headstock (even at high speeds)Smaller radial run-outA BT double contact arbor can also be used in a standard BT machine spindle – and vice versa. The advantages of the double contact are however achieved only when a double contact arbor and double contact spindle are used together.