Square nuts are four-sided nuts as opposed to the more common hex (six-sided) nuts.
The surface area on the flats is larger than hex nuts, which reduces wrench slippage. However, you cannot use hex drivers such as sockets and nut drivers.
Machine screw square nuts are available in smaller sizes and also smaller in width and thickness than regular square nuts.
Machine screw square nuts have flat tops and bottoms—the edges and corners are not chamfered (beveled).
Regular square nuts have a flat bottom bearing surface and a crowned washer-faced top. Regular square nuts are often used with square bolts.
Size: M6/M8/M10/M12/M16/M20
Width across flats: as per size
Thickness: as per size
Thread type: metric corse/fine right-hand thread
imperial thread is available upon request
left-hand thread is available upon request
Material: steel
Grade: 4.8/6.8/8.8/10.9/12.9
Finish: plain/black oxide/zinc plated (galvanized)/hot dip galvanized (HDG)
other kinds of surface treatment are upon request
Technical info: DIN 557
