Sometimes names conjure up all sorts of imaginary visions which have no relation to the product but in this case the name literally means a screw with a button on top with a socket in it. The development of this product seems certain to have happened around the period from 1860 to 1890 with a flurry of patents being lodged in the U S A during this period.
Around the turn of the century there were a variety of different socket designs with triangular and square sockets and wrenches being the most popular. The whole patent process was quite interesting in that whilst the ideas flowed quickly the ability to manufacture the wrenches and screws was a problem too far. In fact it was not until 1908 that Mr P L Robertson of Milton, Ontario in Canada first produced a commercial manufacturing system capable of producing the socket system.
The first hexagon drive came in 1911 by Standard Pressed Steel Company with very expensive screws from England. The wrench systems were a nightmare and caused many a profanity from the engineers that had to use them. It wasn't until the development of the Allen key in 1943 that the system really took off. The Allen key was developed by the Allen Manufacturing Company and the name has stuck with many people believing, wrongly, it was developed by a man called Allen. In practice this method of wrench keys was developed in many different countries and there were many different patents around the world.
The advantage of the socket button screw is that the joints made can be tightened to a much greater strength than an ordinary screw and very similar to a spanner tightened bolt. The head of the screw is round and in a button shape which has no sharp corners to catch on anything and can look quite decorative. They are now made from high tensile grade 10.9 steel self-colour ISO for a high torque attractive finish in a full range of sizes and the good suppliers have a regular in-house stock for regular delivery. The market has grown ever larger being with the different usages that have come into operation, they have taken over a lot of the steel rivet market and are regularly used in metal fabrication, particularly where the flat pack delivery system applies. They are also used in machine manufacture where they can supply the strength needed to join metal plates and brackets together.