For sale is a Brown Sharp No 10 Adapter. Not sure what it is for. 5/8-11 internal thread (see tap inserted for illustration, not included). The internal taper on the thicker part is pretty steep. Definitely much steeper than Morse taper. Throat ID is 0.99 inch (probably 1 inch nominal). Inside, the taper ends, becomes straight, and about 1/2" deeper there are three lips.