Durable L Type Bend Screw Superior L Shaped Right Angle Square Bend Screw Hook

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What is a Bend Screw?

A Bend Screw, also known as a Dog Point Set Screw or Flat Point Set Screw, is a specialized type of fastener designed for precise positioning and securing of one component against another, typically on a shaft or within a bore. Unlike standard set screws with a conical point that can dig into the shaft, a bend screw features a unique curved or radiused end. This design creates a line contact (as opposed to a point contact) with the shaft, significantly increasing the holding power and minimizing stress concentration on the shaft. It is an excellent choice for applications requiring frequent adjustments or where damage to the secured component must be avoided.

Materials

Bend screws are manufactured from various materials to meet different strength, corrosion resistance, and environmental needs.

• Carbon Steel: The most common material, often hardened and tempered for high strength.

• Alloy Steel: Used for applications requiring higher strength and fatigue resistance.

• Stainless Steel: (e.g., 18-8, 304, 316) Provides excellent corrosion resistance for use in harsh environments.

• Brass: Used in applications requiring non-magnetic and non-sparking properties, or in plumbing to prevent galvanic corrosion.

Surface Treatments

Surface finishes are applied to enhance corrosion resistance, appearance, and sometimes lubricity.

• Black Oxide: A common finish that provides mild corrosion resistance and a black appearance.

• Zinc Plating: Offers good corrosion resistance and can be in clear (blue), yellow, or black chromate.

• Nickel Plating: Provides a hard, wear-resistant surface with good corrosion resistance.

• Chrome Plating: Used for high corrosion resistance and a decorative finish.

Specifications

Bend screws are defined by several key specifications.

• Drive Type: Most commonly available in Hex Socket (Allen drive) for high torque application and a clean look.

• Point Type: The defining feature is the Bend Point (curved end).

• Size: Specified by thread size (e.g., M4, M5, M6, 1/4″-20, 5/16″-18) and length.

• Standards: Often manufactured according to standards like ISO 7379 for bend point set screws.

Application Fields

Bend screws are used in precision mechanical assemblies where secure and repeatable positioning is critical.

• Shaft Collars and Hubs: To secure pulleys, gears, and levers onto shafts without causing significant damage.

• Precision Machinery: In adjusting screws for aligning components in optical equipment and measuring instruments.

• Automotive Systems: For securing knobs and controls on steering columns and other shafts.

• Jigs and Fixtures: Where components need to be frequently adjusted and re-secured without losing grip.

An Excellent Case: Precision Gearbox Adjustment in a CNC Machine

In a high-precision Computer Numerical Control (CNC) milling machine, the backlash (play) in the gearbox connecting the servo motor to the ball screw must be meticulously minimized and maintained. Any slippage or movement between the coupling and the motor shaft would result in positioning errors, leading to poor machining accuracy and scrapped parts.

The solution employed by a leading manufacturer was to use hardened alloy steel bend screws with a black oxide finish to secure the coupling to the motor shaft. Here’s why it was the perfect choice:

1. Superior Grip: The curved end of the bend screw conformed perfectly to the radius of the motor shaft, creating a large area of contact. This distributed the clamping force evenly and provided a much stronger grip than a standard cup point set screw, preventing any micro-slippage under high torque loads.

2. Minimal Shaft Damage: Unlike a cup point that digs a crater into the shaft, the bend screw’s design minimized permanent deformation. This was critical because it allowed engineers to make fine adjustments during calibration and re-tighten the screw without worrying about the screw point “walking” into a previously damaged area, which would compromise the set position.

3. Repeatable Precision: The combination of high holding power and minimal shaft damage meant that once the gearbox was calibrated for zero backlash, the setting would remain stable over thousands of hours of operation, even through intense vibration and load cycles.

This application of the bend screw ensured the CNC machine maintained its micron-level positioning accuracy, drastically reducing downtime for recalibration and improving the overall quality and consistency of the machined components. It perfectly illustrates how a simple, well-designed component is vital to the performance of a complex system.