In the case of screw-machine work on round stock whose OD (d) does not need machining (a), keep the amount of metal removal to a minimum by maximizing dimension d1 and minimizing dimension L1, as in (b).

For efficient screw-machine work let the cutting tools feed longitudinally and, if possible, simultaneously. In order to facilitate this, part (a) should be redesigned so that the right-end diameter is the smallest. In addition, the grooves should be narrow in order to avoid special tooling (b).

In the multiple-step machining of a part in screw-machine work, machining time is governed by the deepest step (e.g. in the case of a single radially moving cutter having multiple cutting edges). Hence, part (a) should be redesigned so that all steps have the same depth (b).

(g) Effective Drilling

If only a short portion of a bore is used in a press-fit assembly, stich as in (a), it is not always necessary to ream the entire hole, but it is necessary to leave sufficient clearance for reaming (b).

To start a drill, the surface to be drilled should be perpendicular to the drill axis in order to prevent the drill from skidding, wear and breaking. Adding a flat as in (b) is desirable.