In the face of information technology changes, not all students will have access to the means to prepare for this future of work. In addressing this issue, in this study, the authors investigate the impact of a 'Making as Micro-Manufacturing (M[superscript 2])' model in motivating STEM-activity participation and developing self-efficacy among high-schoolers hailing from an underserved community. The approach involved integrating practice-based learning and activities into a high-school class curriculum resulting in the production of small-batch volumes of products in real-world settings for everyday use like instructional kits for elementary school learning. Pre- and post-surveys were administered to ascertain the differences in students' Making and engineering self-efficacy tendencies. Our results saw increases in the students' Making and engineering self-efficacy across multiple dimensions and in-situ during a production process. In addition, our results also quantify and characterize that kinds of helping behaviours that occur in the students' own self-organised production team.