BT40 Spindle Gripper

Specifications:

• Product: Gripper
• Internal Thread: BT40
• Diameter: 25.9 mm
• Length: 85 mm
• Standard: BT40
• Typical Clamping Force: Approx. 2500 to 3500 kg
• Claw Material: Hardened alloy steel

Description of the BT40 Gripper

The BT40 spindle gripper (or drawbar mechanism) is a component housed within the CNC machine’s spindle; its function is to grasp and retain the BT40 tool holder by engaging its pull stud.

Simply put, when the BT40 tool enters the spindle, the gripper locks onto the pull stud, and the force of Belleville springs holds the tool securely in place. During a tool change, a pneumatic or hydraulic cylinder applies pressure, causing the gripper to open and release the tool.

Key Components of the BT40 Gripper

1. Gripper fingers (typically 6 or 8 segments)
2. BT40-compatible pull stud
3. Disc springs
4. Drawbar
5. Bearings and bushings
6. Applications: CNC milling machines, VMCs, Automatic Tool Changers (ATC)

Signs of Gripper Failure

• Loss of tool accuracy
• Vibration during cutting
• Tool ejection
• ATC errors
• Pull stud wear
• Important points regarding grippers:

Ensure the specific BT40 pull stud is used – periodic lubrication and servicing are crucial – loss of spring force = risk of tool detachment.