What Are Miniature Screws?
Miniature screws are small-diameter screws used in devices such as cameras, eyeglasses, and precision instruments. They feature smaller heads compared to standard screws and are typically M2 or smaller. Materials used for miniature screws include iron, brass, and stainless steel, varying based on their application. They are also known as cross-holed small screws for precision instruments, No. 0 screws, precision screws, camera screws, and eyeglass screws.
Applications of Miniature Screws
Miniature screws are utilized in fine instruments such as precision devices, notably in cameras and eyeglasses. The miniaturization trend in machinery has expanded their use, increasing the demand for even smaller screws, referred to as No. 00.
Operating Principle of Miniature Screws
The fastening principle of miniature screws is similar to that of larger screws, utilizing a spiral slope or lead angle to convert rotational force into tensile force. Due to their small size, miniature screws are not designed to provide significant axial force, and excessive torque may damage the screw’s cross groove.
Varieties of Miniature Screws
Miniature screws come in various types, classified from Type 0 Class 1 to Type 0 Class 3, with “Type 0” indicating the screwdriver size needed for the screw head. “Type 1” to “Type 3” denote the size and thickness of the screw head, with higher numbers indicating larger and thicker heads. There are also distinctions between round top and flat head screw heads, with three different sizes available for each.
Additional Information on Miniature Screws
Main Materials and Surface Finishes of Miniature Screws
Common materials for miniature screws include steel, stainless steel, titanium, and brass, each selected based on strength and application requirements. Electrolytic corrosion, a potential issue when different metals interact, should be considered in design, especially in critical applications. Surface treatments, such as black paint, trivalent chromate, and various platings, are selected based on the application’s needs for corrosion resistance, appearance, and cost.
Guidelines for Using Miniature Screws
- Ensure the tightening force is within the allowable range to prevent damage to the screws and the materials being fastened.
- Consider the repetitive force applied to the screws, ensuring it remains within the allowable range, especially in vibratory conditions.
- Maintain appropriate pressure on the seating surfaces to avoid damaging the tightened object.
- Avoid causing damage to the object being tightened during the fastening process.