There are a variety of miniature screws and fasteners currently available. Depending on the type and size of project, one or more of these items may be what is needed to complete the job:
- Custom screws
- Custom set screws
- Custom shoulder bolts
- Micro fasteners
- Micro screws
- Miniature screws
- Small screws
- Tiny screws
- Undersized screws
Heat-treated, High-strength alloys are used to make most screws. The 4140, for example, has Rockwell C hardnesses of 32-to-43.
When working on PCs, there are two basic screw thread types that are used for construction and repairs. The first is a self-tapping screw that is used to fasten a PC’s fan to the case. It can also be used for ventilation-related plastic parts, such as ducts. In addition to having a flat-head, this screw tends to be ten millimeters long.
The second type of screw is United National Coarse (UNC) 6-32 standard. One of the benefits of this type of screw is that it can be used with a #2 Phillips screwdriver.
Since strength is a concern, it’s important to note that fine-threaded screws are actually a bit stronger than other types of screws. This is due, in part, to their taking up less space, or less of the area in which they’re placed. When comparing a one-fourth UNF thread with a comparable UNC screw, the UNF is approximately 14% stronger.
There are two ways to tighten these screws: by feel and by using a torque wrench. The Machinery’s Handbook states that when screws are tightened by feel, they are plus-or-minus 35% accurate. When screws are tightened with a torque wrench, however, the accuracy is improved by plus-or-minus 25%.
Another type of fastener is the shoulder screw. It is effective with creating single-supported linkages and when parts need to rotate.
Shoulder screws are usually made of cold-drawn, 303 stainless steel. These screws are available in the following commercial-grade standard sizes: ASME B18.3 for inches and B18.3 .3M for metric sizes.
The shoulder diameter and length determines its specification. A one-fourth-times-one-inch screw, for example, would have a shoulder length of one-inch, and a shoulder diameter of one-fourth inch.
When miniature screw are needed to complete or repair a project, there are a variety from which to choose. These screws can also be custom-made when needed.