Measurement of Taper Fittings

ONE of the standards adopted earliest by the Society is the list of taper fittings. This standard was adopted in 1914, and has been in use ever since with little revision. Saying that the indicated method of dimensioning and stating limits for taper fittings is not practical, at least in some cases, the author suggests various methods for expressing the tolerance in terms of the longitudinal position of a basic diameter.

Another point brought out is that the sides of the keyway are not parallel to the taper. In the 2-in. size, for instance, if the bottom of the keyway is made parallel to the extreme element of the taper as it existed before cutting the keyway, the depth at the side is computed to be 0.0318 in. at the large end of the taper and 0.0392 in. at the small end, a variation of 0.0074 in. between the two ends.