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During the use of spring collet, if it is used with high precision, it is usually boring first, so that the accuracy of the collet is the accuracy of the spindle. For the spring collet after the front end is quenched, as long as it is used reasonably, the life factor does not need to be considered at all. The accuracy of corn tooth type and special-shaped spring chucks is determined by the manufacturing accuracy of the chuck.

Spring chucks can be used not only to position and clamp turning workpieces, but also to position and clamp cutting tools, grinding and milling workpieces, or many other situations. The external thread of the machine tool spindle tie rod is connected and tightened with the internal thread of the rear end of the spring chuck, generating an axial pulling force. Then the cone surface at the front end of the machine tool spindle, called the locking angle, converts the axial pulling force into a force perpendicular to the spring clamp. Clamping force at the center of the head. Not only that, the clamping force can also be expanded through the locking angle. According to calculations, the clamping force of the spring collet can be expanded by 3-4 times according to different locking angles.

The spring chuck is a simple process device, but it has many main factors that affect the clamping force. Understanding the basic principles can help the workpiece (or tool) be clamped correctly and faults quickly found. The following introduces several main factors that affect clamping force and summarized usage experience:

(1) Axial force. The pull rod applies an axial pulling force to the spring collet. In the use of the spring collet, the axial force pulling force can be applied in different ways, but its principle of action is basically the same. Therefore a large axial pulling force will produce a large clamping force and vice versa. Generally, the axial tension of the tie rod can be adjusted on the CNC machine tool.

(2) When using a spring collet, the locking angle of the collet will determine the radial clamping force that the spring collet can provide under the same axial tension. This is usually determined by the machine tool manufacturer and the spring. The chuck manufacturer decides. The selection of locking angle should be based on economy and reliability, and should be determined according to the type of machine tool, usage conditions (dynamic and static) and usage (workpiece and tool).

(3) The friction between the workpiece (or tool) and the spring chuck will directly affect the firmness of the clamping (but does not affect the size of the clamping force). The greater the friction, the firmer the workpiece clamping, and vice versa. In order to overcome the relative rotation or axial movement between the collet and the workpiece (or tool), various measures can be taken during the manufacturing process of the collet to increase the friction. For example, the inner hole of the collet is intentionally made Sawtooth shape or impregnating carbide micro-grains on the clamping surface, etc.

(4) Friction between the spindle taper surface and the spring chuck at the locking angle. The amount of friction also directly affects the strength of the spring chuck's clamping force on the workpiece. If the friction force is too small and the clamping force is insufficient, the relative rotation of the workpiece will occur; while if the clamping force is too large, the spring chuck will wear faster.

(5) In actual use, the spring chuck must be loosened frequently to replace workpieces. For example, when used on a turning machining center, a layer of lubricant can be sprayed on the surface of the inner hole of the spring chuck when loosened. If possible, coolant can be used to lubricate and replace the workpiece. Well, this can not only flush the debris from the spring chuck, but also provide a good lubrication effect. Regularly applying grease to the locking corners of the collet can reduce long-term wear and increase clamping force. Other materials with better lubricating properties may also be used, including high-quality greases or wax-based materials with EP (Extreme Pressure) properties.

(6) Reasonable selection of the clamping diameter of the spring chuck can ensure that the spring chuck produces the maximum clamping force on the workpiece and achieves the best clamping state, thereby ensuring high quality and high precision in machining. If the inner hole diameter of the collet is too large, the workpiece will only be clamped by the hole of the collet when the chuck is closed, which is likely to cause a geometric mismatch between the outer circle of the workpiece and the inner hole of the collet. Therefore the clamping force is reduced. If the diameter of the inner hole of the spring chuck is too small, only the inside of the inner hole of the chuck is in contact with the workpiece when the chuck is closed. Although the clamping force is increased, it will cause the chuck and the workpiece to be out of axis. A spring chuck with a specified size can only clamp and position workpieces with corresponding diameters.