Contact Us    |    About Us   |   EMG Blog

Pull Studs Retention Knobs from EMG Precision EMG Pro

Shop By Category

Pull Studs / Retentions Knobs

Pull studs, sometimes referred to as retention knobs, are used for connecting tool holders to the machines spindle drawbar. Available with or without through coolant and in an O-Ring style to prevent coolant leakage.

Pull Stud / Retention Knob FAQs

Pull studs (also called retention knobs) are the link between the machine drawbar and the toolholder. Pulling forces can reach 3000 daN on SA 50 spindles, making the superior material and hardening quality of EPB pull studs important.

Precision machining guarantees precise positioning and safe locking of the holder in the spindle. Most machines require a standard pull stud design (DIN, ISO, BT, CAT) and some require a specific design. 

If Pull studs become damaged or worn, this can effect the correct and effective seating of the tool holder in the spindle tool holder cone. Not to mention, a damaged pull stud could cause detrimental damage to your spindle. It is important to check your pull studs every week to ensure that they are tight on the tool holder.  If they loosen up, then you run the risk of the tool holder not being pulled up tight into the spindle or worse, the tool holder could fall out of the spindle or vibrate very badly.