Drilling Tools

BRACES

Braces guide auger bits and drills. Attaching a screwdriver bit converts them into powerful screwdrivers.

Drilling is done by turning the handle or center section in a circular motion. Pressure for drilling is given by bearing down on the head of the bit brace with the heel and palm of the hand. The head on the best bit braces is mounted on ball bearings so that it will turn freely from the rest of the brace.

Most braces incorporate a ratchet control which permits the user to make half-circles when there is no room for a full circle.

BITS

Bits (drill points) have a variety of uses with braces and drills. Each bit and drill is designed for a particular use and should be used for its intended job.

Bit diameters are usually marked by a single number-the numerator of a fraction. For example, an auger bit, which is marked by 16ths of an inch, with a number 8 would stand for 8/16" or 1/2". Twist bits are usually marked in the same manner by 64ths of an inch. Thus a No. 8 bit would stand for 8/64" or 1/8".

Countersunk bits widen holes so flathead screws may be flush mounted below the surface for a finished appearance.

Expansive bits take the place of many larger bits. They are adjusted by moving the cutting blade in or out by a geared dial or by a lockscrew to vary the size of the hole. Mounted below the surface for a finished appearance.

Carbide-tipped bits are used for drilling into masonry surfaces. They feature two machined-in spiral threads, one for each cutting edge, to provide passageways for all dust and cuttings from the bottom of the hole. Diameters of carbide tips are the same as the full diameter of the body. A carbide-tipped bit can be used in electric drills, drill presses or hand drills for drilling holes in brick, tile, cement, marble and other soft masonry materials.

Twist-drill bits are used in both wood and unhardened metals to make clearance holes for bolts, screws, etc., and to make holes for tapping. Only bits marked HS or HSS are suitable for drilling in metals. Common sizes run from 1/16" to 1/2" diameter by 64ths.

Auger bits are most commonly used with a brace for drilling holes in wood. Their length varies from 7" to 10". Dowel bits are short auger bits from 5" long. Long (ship) auger bits range from 12" to 30".

Spade bits are used in electric drills and drill presses for fast drilling of holes in wood. Electricians use them for drilling clearance holes for wire in floor beams. Bits have a forged, flat paddle with a point and cutting edges on one end and fit a 1/4" drill on the other. Bits are heat treated and cutting angles finish ground. Common sizes run from 3/8" to 1-1/2" in diameter, in 1/16" progression, and are about 6" long.

Power-bore bits have a working end similar to auger bits and, like spade bits, are used in conjunction with power drills. Power- bore bits produce a smoother hole than spade bits and are used for fine work, such as cabinet making.

Step bits have a graduated design so that variously sized holes can be cut without changing bits. Bits are designed for use with power drills and have self-starting tips eliminating the need for center punching. They can be used on all materials, but are especially designed for use on metals.

PUSH DRILLS

A push drill, similar in appearance to a push-pull screwdriver, is operated by a push-pull movement for light jobs. Most push drills have space in the handle for storing extra drill points, bolts, screws, etc.

HAND DRILLS

Hand drills are limited to light work. They feature adjustable drill chucks to permit easy changes of drill points from ½" to 1/16". Drilling action comes from turning a hand crank on the side of a drill frame.

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Check your state and local codes before starting any project. Follow all safety precautions. Information in this document has been furnished by the North American Retail Hardware Association (NRHA) and associated contributors. Every effort has been made to ensure accuracy and safety. Neither NRHA, any contributor nor the retailer can be held responsible for damages or injuries resulting from the use of the information in this document.