This article explores assessment actions –as an aspect of classroom communication –and how they are expressed in sloyd teaching; with a formative aim centering on pupils’ learning and (the teacher’s) own teaching practice, respectively. In this context, the teacher holds a central role, mediating sloyd knowing through (communicative) verbal and physical actions, acting as an authoritative guidefor pupils’ learning, by making perceptually tacit knowing discernable thanks to pre-established confidence for the teacher in question. Besides authoritative guiding, another theoretical starting point of the article is sociomateriality; a perspective considering physical objects as resulting from connections and activity, hence influencing on the (more) social sphere of actions and activity. The method used is multimodal interaction analysis of three video-recorded sequences of teacher/pupil interaction in a sloyd-classroom setting. To sum up, the findings of the article display how formative assessment in the sloyd context consists of the teacher adapting questions posed to ascertain the knowing of the pupil, then waiting to see how/what/if the pupil performs, whilst being provided –gentle but ample –authoritative guiding to help in the process. The main contribution of the study is establishing the role of formative assessment within sloyd education. The research project has been conducted within the framework of Stockholm Teaching and Learning Studies (STLS), entailing the active involvement of the teacher in question as co-author of the article.