Cobalt Step Bits Appraisal

Step Drill Bit Set with Wooden Storage Box

This is a modular set of step drill bits, commonly referred to as 'unibits,' housed in a specialized wooden presentation and storage case. The set includes at least four distinct bits of varying sizes designed for drilling concentric holes in thin materials مثل sheet metal or plastic. The largest bit is labeled for a 4-32mm range, followed by a 4-20mm bit, and a 4-12mm bit. The bits are constructed from high-speed steel (HSS) and feature a dark surface treatment, likely a black oxide or titanium carbonitride (TiCN) coating, which is intended to reduce friction and extend the tool's lifespan by resisting heat. Each bit is characterized by its conical shape with increasing step diameters and a spiral flute design to facilitate efficient chip removal during the drilling process. The shanks appear to be hexagonal, allowing for quick-change compatibility with impact drivers and standard drill chucks. The wooden box features foam padding inside the lid and a custom-cut wooden insert to keep the tooling secure. Notably, the internal wooden divider has handwritten text in black ink that reads 'JUST DOWN YOU B***H', which is a non-factory personalization. The overall condition shows signs of moderate use, with some light metallic dust and wear on the coating of the bits, and scuffing on the exterior of the wooden box. The craftsmanship suggests a mid-range commercial utility set, likely manufactured within the last 10 to 20 years. No specific manufacturer brand is visible on the tooling in the provided image.