A joint effort between Boeing and the National Institute of Standards and Technology (NIST) was undertaken for validat - ing and evaluating STEP AP238 (STEP-NC) Conformance Class 1 (CC1) for 5-axis machining. STEP-NC is a new manufactur- ing standard to support "design anywhere, build anywhere, a nd support anywhere." The joint Boeing/NIST validation inten ded to prove that five-Axis AP-238 programs with tool center pro- gramming (TCP), as opposed to that of axis movement data, are portable. Current RS274 "G code" part programs that use axis movement data are bound to a single CNC, are ineffective on different machine tools, and cannot be used for the exchangeof information between process planning, work preparation, t ool- ing, and other production processes. All of these obstaclesadd considerable time and cost to the production life cycle of a m a- chine part. This paper discusses the joint Boeing/NIST STEP -NC TCP validation work. The major findings were that STEP-NC TCP geometrical data is portable across different 5-axis co nfig- uration CNCs. This came with a caveat, that although CNC pro- grams can be "data-neutral", they are not necessarily "proc ess- neutral".