Abstract: A downhole device (15) comprising: a body (10) with a bore; at least one wheel (20) or other retained component; an engagement member (40) for engaging the wheel with the body. A retaining member (31) retains the engagement member (40) in place, the retaining member (31) extending along the body (10) and in the line of the main axis of the engagement member (40) so that it abuts. Embodiments allow for more convenient and more reliable retaining of wheels or other components in the device especially reducing the need for using threaded connections, which are prone to failure.

Abstract: A downhole device (15) comprising: a body (10) with a bore; at least one wheel (20) or other retained component; an engagement member (40) for engaging the wheel with the body. A retaining member (31) retains the engagement member (40) in place, the retaining member (31) extending along the body (10) and in the line of the main axis of the engagement member (40) so that it abuts.