b. Reaming. Reaming is a machine operation that smoothes out the surface of a drilled hole. From a drawing standpoint, reamings are drawn the same way that drilled holes are drawn. The call out notes, however, are different as shown in figure 87, view B (on the previous page).
c. Counterboring. Counterboring is a machine operation in which part of a drilled hole is redrilled to a larger diameter (figure 87, view C).
d. Countersinking. Countersinking is a machine operation in which a drilled hole is redrilled to produce the tapered shape shown in figure 87, view D. Countersinks are usually made at 82°, but they may be drawn at 90° (45° on each side).
Was this article helpful?