In the metal industry, various machining techniques are available. The more well-known techniques are, milling, cutting and grinding. Spark erosion is also a machining technique which uses a spark transfer to remove material. The removed material however is so small that it cannot be compared to the amount of material removed through other techniques such as cutting. At HSOS Industrial Services we only use a Eromobil Spark, using this we can bore or tap apparatus and motors without damaging the threads. It is also possible to erode broke bolts by using a square electrode first and a socket second.