JM Performance Products Changes Material Used in Retention Knobs

JM Performance Products has begun changing the material used in the production of its retention knobs from 8620H to 9310H grade steel. The 9310H material offers 40% greater tensile strength, the company says, which is expected to meet changing milling demands. This change in material predominantly affects the 30- and 40-taper knobs, although some 50-taper knobs have been included.  

The company’s high-torque knobs are designed to eliminate toolholder expansion, which is said to be the main cause of vibration, chatter, runout, poor tool life, poor tolerances and other milling issues.

Having identified a design flaw regarding the expected cross-sectional strength of the knobs, JMPP has begun modifying the size of the coolant holes in many of the 30- and 40-taper knobs. The knobs will continue to supply more coolant than demanded, but will be sized to increase the cross-sectional strength of the knobs.

As the retention knobs made from 8620H are phased out, they will be replaced by an HS (High Strength) version.