Explores the implementation process of the customer‐supplier partnership in the machinery industry. Aims to assess the dynamic impacts on performance of various practices that are generally regarded as typical of a customer‐supplier partnership. Also, investigates internal consistency of various practices and possible path dependencies. Shows, in the case of single sourcing, the complementarity and the synergistic effects of co‐design, sharing production plans, dedicating up‐stream capacity and assuring down‐stream demand. Finds the key role of a complete performance control system to monitor delivery, quality and cost performance, even when tight control over suppliers might be regarded as less crucial due to trust and long‐termism. Discusses the issue of dedicated EDI assets and shows that, at least in some cases, delaying investments might significantly reduce risks of sunk cost for both partners. Shows that, while some players on both sides of the relationship perceive the relationship as a “win‐win” situation, others play a “zero sum game”.