A few years back during building the TFG pavillion at Keene I recall watching Paul Russell using an adze to remove the excess above and below the the faces of a tenon and he even finished the tenon faces with the same tool. The part being worked on was placed on the ground and held down by the foot. During the examination of any old buildings this practice would not immediately be obvious since the tenon faces are concealed from view.
If I were applying a chamfer to the lower edges of a floor joist I would more likley use a hand axe to make discrete cuts and then use a draw knife to clean between the cuts down to the required profile. The stops at either end would be done using a chisel.