Hex Machine Screw Nuts, Grade 2, Electro Zinc Plated Steel & Clear Finish, By Fastenere. Machine screw hex nuts are specifically designed for use with machine screws. Machine screws are almost always used in conjunction with a mating bolt to fasten multiple parts together the two partners are kept together by a combination of their threads friction with slight elastic deformation which is a slight stretching of the bolt and compression of the parts to be held together.
eBay