Drill Presses MACH 112 Cutting Tools Measurement OBJECTIVES

Drill Presses MACH 112: Cutting Tools & Measurement

OBJECTIVES After completing this unit, you should be able to… • Identify basic drill press types and explain their differences and primary uses. • Identify the major parts of the basic drill press. • Identify the major parts of the radial arm drill press.

THE DRILL PRESS Introduction • The primary use of the drill press is to drill holes. ▫ It can be used for countersinking, counterboring, spotfacing, reaming & tapping.

THE DRILL PRESS Major Parts • Fig. H-13 labels the parts of the drill press that you should remember. The spindle rotates within the quill, which does not rotate but carries the spindle up and down.

THE DRILL PRESS Machine Capacity • Machine capacity is measured by the diameter of work that can be drilled. Fig. H-12 Drill presses are measured by the largest diameter of a circular piece that can be drilled in the center.

THE DRILL PRESS Drive System Fig. H-15 View of a variable-speed drive. The variable-speed selector should be moved only when the motor is running. It is possible to choose the exact speed for the drill size and material with this drive (Clausing Industrial, Inc. ). Fig. H-14 View of a vee-belt drive. Spindle speeds are highest when the belt is in the top steps and lowest at the bottom steps (Clausing Industrial, Inc. ).

THE DRILL PRESS The Radial Arm Drill Press • The most versatile drilling machine. ▫ Size is determined by diameter of the column & length of the arm measured from the center of the spindle to the outer edge of the column.

THE DRILL PRESS Multi-spindle Drilling Machine

THE DRILL PRESS Gang Drilling Machine

THE DRILL PRESS Magnetic Base Drilling Machine

THE DRILL PRESS Work/Tool Holding • Drill Sleeves & Sockets

Using a drill drift Fig. H-40 Cut away of a drill & sleeve showing a drift in place. • Use rounded corner of drift in the top of the hole to prevent squaring of spindle hole.

THE DRILL PRESS Drill Press Vise

C-Clamps

THE DRILL PRESS Drill Jig

OPERATING DRILLING MACHINES tab Work Holding • One method of work holding is to use strap clamps and T-bolts. Fig. H-74 Strap clamps: (a) U-clamp; (b) straight clamp; (c) finger clamp. Fig. H-75 T-bolts. Necessary for safety, workpiece rigidity and good workmanship.

OPERATING DRILLING MACHINES tab Work Holding • The clamp must be kept parallel to the table by the use of step blocks. ▫ The T-bolt should as close to the workpiece as possible. • Parallels are placed under the work at the point where the clamp is holding blocks. – This provides a space for the drill to break through without making a hole in the table. Fig. H-78 Parallels of various sizes.

OPERATING DRILLING MACHINES tab Work Holding • A thin or narrow workpiece should be supported close to the drill, or it will spring down under the pressure of the drilling. Fig. H-79 Thin, springy material is supported too far from the drill. Drilling pressure forces the workpiece downward until the drill breaks through, relieving the pressure. The work then springs back, and the remaining “fin” of material is more than the drill can cut in one revolution. The result is drill breakage.

OPERATING DRILLING MACHINES Work Holding • C-clamps of various sizes are used to hold work on drill press tables and on angle plates ▫ Angle plates help hold odd-shaped parts for drilling. • Drill press vises are frequently used for holding small workpieces of regular shape & size. Fig. H-81 Drill press vise. Small parts are held for drilling and other operations with the drill press vise (Wilton Corporation). tab

OPERATING DRILLING MACHINES tab Work Holding • Vises should not be used if work does not have parallel sides. ▫ The groove in the vise jaws holds small cylindrical parts ▫ Larger cylindrical parts can rest on the bottom surface of the vise. ▫ The workpiece must be supported so the drill will not go into the vise. Fig. H-82 Part set up in vise with parallels under it.

OPERATING DRILLING MACHINES tab Work Holding • Angular vises can pivot a workpiece to a given angle so that angular holes can be drilled. ▫ Another method of drilling angular holes is by tilting the drill press table • If there is no angular scale, a level may be used to set up the correct angle for drilling. – This method will not be accurate if the drill press is not level. Fig. H-83 Angle vise. Parts that mus be held at an angle to the drill press table while being drilled are held wit this vise (Wilton Corporation).

OPERATING DRILLING MACHINES tab Work Holding • Angle plates are also sometimes used for drilling angular holes. Fig. H-84 View of an adjustable angle plate on a drill press table using a protractor to set up. • The drill press table must be level. Fig. H-85 Checking the level of the table.

OPERATING DRILLING MACHINES tab Work Holding • Vee blocks come in sets of two, often with clamps for small-sized rounds. Fig. H-87 Setup of two vee blocks and round stock with strap clamp. Fig. H-86 Set of vee blocks with a vee-block clamp. • Larger-size stock is set up with a strap clamp over the vee blocks.

OPERATING DRILLING MACHINES tab Work Holding • The workpiece is lightly clamped in the vee blocks, and the punch mark is centered as shown. ▫ The clamps are tightened, and the drill is located precisely over the punch mark by means of a wiggler. Fig. H-88 Round stock in vee blocks; one method of centering layout line or punch mark using a combination square and rule.

OPERATING DRILLING MACHINES tab Work Holding/Locating • Jigs & fixtures are specially made tooling for production work. ▫ The use of a jig ensures exact positioning of the hole pattern in duplicate and eliminates layout work on every part. Fig. H-91 Typical box jig. Hardened bushings guide the drill to precise locations on the workpiece.

OPERATING DRILLING MACHINES tab Locating • A wiggler can be put into a drill chuck to locate a punch mark to the exact center of the spindle. Push on the knob near the end of the pointer with a 6 -in. rule or other piece of metal until it runs with no wobble. Fig. H-89 Wiggler set in offset position. Fig. H-90 Wiggler centered.

THE DRILL PRESS Review Questions • Other than a standard drill press, name four types of drill presses. • What type of work is a radial drill press best suited for? • What are drill sleeves and sockets used for?

Questions?