Hex nuts are the most widely used nuts and will work for most applications. They are standard thickness and can be installed with a wrench or socket set. Machine screw nuts, is a subset of finished hex nuts designed for use with machine screws, which are typically much smaller than bolts.
- Size: #4-40
- Very common and versatile nut
- Same in design as a standard hex nut, but smaller to accommodate machine screw sizes
- Screws onto a machine screw of the same thread size
- Often used with a washer with same diameter opening
- Thread type: coarse: thread class: UNC-2B
- Specification met: ASME B 18.2.2 and ASME B1.1