© American Society for Engineering Education, 2018. The objective of this paper is to outline a new model for motivating STEM participation and developing self-efficacy among high-schoolers, and to detail the major implementation activities involved, preliminary impressions/results, and lessons learned. In this model titled, \"Making as Micro-Manufacture (M3),\" high-variability low-volume products were manufactured in real-world settings and for a real-life purpose. The model combined \"Making\" with engineering concerns attendant to manufacturing at micro scales (tens to hundreds of parts) along with domain knowledge (elementary school science). Practice-based learning was implemented, in which a cohort of high school students from an underserved border community in Texas worked as an autonomous Making-Production Team (MPT) to produce instructional hands-on science kits for their own community's elementary school. By working in a scenario simulating professional practice, the MPT members pragmatically integrated Making activities with aspects of production scheduling, inventory, and supply-chain management. The eventual goal of this activity was for the MPT members to learn engineering concepts and develop a STEM self-concept that only such thick practice could provide. Supported via distance mentoring and summer training workshops by a Texas A&M University's engineering technology undergraduates, the approach was tested in a rural underserved border community with populations typically underrepresented in STEM. Evaluation mechanisms consisted of questionnaires, interviews and video recordings of work sessions. Altogether, the preliminary results and lessons learned helped shed light on aspects of implementation critical to the successful full-scale deployment of such self-sustainable MPT teams, both in developing themselves, as well as in serving and growing within their own close-knit community.