466 Modern Metalworking Copyright Goodheart-Willcox Co., Inc. Small drills are held in a standard Jacobs chuck mounted in the machine spindle. See Figure 26-60. Larger, taper shank drills are held in a sleeve or adapter, Figure 26-61. Boring is done with a single-point cutting tool fit- ted in a boring head, Figure 26-62. The boring tool is held in the spindle by a collet adapter. A wiggler, Figure 26-63, will aid in aligning the machine if holes are to be drilled before reaming or boring. A dial indicator must be used to realign exist- ing holes for boring, Figure 26-64. 26.8 Vertical Milling Machine Operations The vertical milling machine is a highly versatile machine tool for milling, drilling, reaming, and bor- ing. It differs from the horizontal mill in that the spin- dle is normally in a vertical position. The spindle head, Figure 26-65, swivels 90° left or right for angular work. The ram on which it is mounted can be adjusted in and out and, on many vertical mills, revolves 180° to a hori- zontal plane. The swivels are graduated with a Vernier scale to ensure accurate angular settings. Goodheart-Willcox Publisher Figure 26-60. Drilling on a horizontal mill. Milling machinee Milling machin spindle Adapter for taper shank accessories Work Feed Goodheart-Willcox Publisher Figure 26-61. Taper shank drills can be used by fitting an adapter to the spindle. Milling machine spindle Taper shank drill Sleeve Adapter for taper shank accessories Work Goodheart-Willcox Publisher Figure 26-62. Boring permits large holes to be machined to close tolerances. Work Boring bar o e e d al Mic cr om et er d ia for setting depth of cut Taper to fit milling machine spindle Goodheart-Willcox Publisher Figure 26-63. The position of a hole can be located with a wiggler. Goodheart-Willcox Publisher Figure 26-64. Existing holes can be realigned on a milling machine with the aid of a dial indicator. Jacobs chuckckhu Jacobs c mounted in spindle Work (stationary) (