Abstract: A threading tool intended primarily for use as an electrical wiring pencil has a tubular body housing a manually operable brake member which can be moved into frictional engagement with the edges of a rotatable spool to restrain movement of connecting wire through the body. The brake member is housed in a recessed channel which is open to the outside of the body along its entire length via a relatively narrow slot. The slot and the channel are open at the spool end of the tool to allow easy assembly of the brake member into the tool. Insertion and removal of the spool is performed by prising apart jaws at the end of the body. When inserted, the spool holds the brake member in place.