Unusual application for Horn carbide inserts

André Gall, founder of German firm WireStyle, uses in-house developed machines to create works of art based on a photo or graphic using an average of 8,000 nails and a long thread. Twelve nails are hammered into a polystyrene sheet every second to create a canvas for the thread picture. Each nail is cut from a reel of aluminium wire by a pair of indexable carbide inserts from Horn’s S274 tool system.

A picture is created by a single thread measuring around 1,200 metres. To determine the exact path as it is being wound around the nails, the WireStyle team developed complex algorithms to identify and enhance the contrasting edges in the original image and calculate the individual nail pattern. More thread is used in the darker parts of the picture than in the lighter areas and the reproduction is better and less expensive than could ever be achieved by hand.

Gall studied physics at the University of Karlsruhe and has always been interested in mechanical and production engineering. He personally built the first prototypes of the nail and thread machines and the WireStyle company was born. In 2022, he presented his pictures on the popular German TV start-up show, Die Höhle der Löwen (The Lions’ Den).

To make thread paintings affordable for customers, the machines have to operate at high speed. Due to rapid acceleration at up to 5g, Gall favoured lightweight construction and employed a lot of carbon fibre. The machine stretches about 50 centimetres of thread per second around the nails, which are between a few millimetres and a few centimetres apart. During the process, the eye is barely able to follow the thread puller.

Two opposing S274 inserts from Horn, which are normally used for grooving and side turning components in a lathe, are clamped in the nailing head of a WireStyle machine. Precise cutting of the wire is ensured by the sharpness of the inserts, which are ground with a small wedge angle. Accuracy and reliability are very important, as each nail has to be exactly 20 mm long.

Due to the stable seating of each insert, when it is indexed the changeover accuracy is better than 0.003 mm. It ensures that the positions of the cutting edges are neither too far apart, which would compromise cutting of the wire, nor too close, which would chip the sharp insert edges.