Good tolerance- and variation management is essential to achieve high value adding products with cost-effective processes. The link between Tolerance Engineering and popular manufacturing improvement philosophies such as Lean and Six Sigma is, however, not always that clear. The possibilities and limitations of these two approaches on Tolerance Engineering are discussed in this paper. The case describes cross-collaborative improvement work within industry on tolerance and variation management which is similar to a work model called “Closed Loop Tolerance Engineering” (CLTE). The case is focused on the process of revising existing drawings and tolerance specifications for the manufacturing of products with a long lifetime. Although both Lean and Six- Sigma have been important for the improvement work in the case company for several years, there is still a gap to be filled on tolerance and variation management. The novelty of this paper is found in the link between an industrial case on improvements and an academic model (CLTE) for cross-collaborative engineering on variation and tolerances.