The invention relates to measuring gauges for measuring thread diameters and thread depths. Go and No-Go gauges are known where a stem has a Go gauge to one end an a No-Go gauge at the other, for checking thread diameter and pitch. The invention seeks to improve on the checking of thread depths whilst retaining an ability to check diameters and pitch, an objective met by a construction comprising a threaded plug to form a Go gauge to one end of a stem, a second threaded plug to form a No-Go gauge to the opposite end of the stem, a body slidably mounted on the stem, a means associated with the stem and the body to sense the relative positions of the stem and the body, and a means on the body to provide a digital read-out of the sensed position.