In at least one illustrative embodiment, an adjustable joint comprises a housing, a pair of wedges arranged in the housing, and a threaded fastener engaged with at least one of the pair of wedges. The housing may include a first cavity that is sized to receive a spherical end of a shaft and a second cavity that is sized to receive a tube. The pair of wedges may be arranged between the first and the second cavities. The threaded fastener may be configured to (i) move the pair of wedges away from one another when rotated in a first direction and (ii) move the pair of wedges toward one another when rotated in a second direction opposite the first direction.