Graphs relating surface roughness to feed speed and depth of cut for brass and steel bars. For constant feeds, the surface roughness will decrease as the tool nose radius increases. This is simply because there is more cutting surface in contact with the work.
Less material needs to be removed near the center of the cutter for each revolution.
The surface roughnesses given in the notes are incompatable with the values we obtained in the lab. The surface roughness of steel is higher than the roughness of brass for given feeds. It is approximately a two to one ratio. See the graphs in part 1.