An experimental study has been made of the chip-tool interface and its evolution in the low speed cutting of metals. Specially prepared transparent glass and sapphire tools have been used to cut commercially pure metals such as lead, aluminium and copper. The chip-tool interface has been observed in situ using optical microscopy and recorded on film and video tape. By observing the motion of inhomogeneities in the chip, and pro-filometry of the chip and tool surfaces, it has been established that there is intimate sliding contact between the chip and the tool at and near the cutting edge. Farther away from the cutting edge and close to the end of the chip-tool contact, metal transfer and sticking are observed between the chip and tool surfaces. It has been shown that metal deposition on the tool rake surface initially occurs near the end of contact and progressively extends outward and away from the cutting edge as the length of contact increases. The sticking and sliding zones are unchanged when these pure metals are machined with tungsten carbide tools.