* Toggle bolts and screw anchors are used where the back of the wall is inaccessible, such as drywall and hollow concrete block.

The toggle fastener works on a spring principle. The holding arms open after the screw and holder are inserted into the hole, gripping the wall as the screw is tightened. The bolts are selected according to the thickness of the diameters from 1/8"-1/2". Fixture to be mounted must be assembled with screw and holder before inserting it into wall.

* Another form of anchor, the molly bolt, consists of a screw in a metal sleeve. When the sleeve is inserted into a pre-drilled hole and the screw is turned, the sleeve spreads. The screw can be removed and inserted in the fixture to be mounted and replaced.

* Plastic screw anchors can be used with wood or sheet metal screws. The anchors are inserted into a predrilled hole and the screw is driven through the anchor into the wall. Anchors range from 3/4" to 1-3/8" long. Another kind of plastic anchor functions like a toggle fastener with sizes from 3/4" to 3-1/2" depending on the thickness of door or wall material.

Other forms of screw and bolt anchors snap into place. These screw anchors, suitable for hollow and solid walls, 1/8" and greater thicknesses, pop open and lock into place before the screw is inserted. One anchor accepts size #6-#14 screws, but only uses a 5/16" drill size. The screw can be removed and replaced.

* The bolt, hollow wall anchor is installed separately from the fixture, permitting the fixture to be removed without dislodging the anchor. The anchor is adjustable for wall thicknesses up to 2-1/4" with bolt diameters from 3/16"-1/2".

* Another fastening system used for hollow surfaces is the wall rivet. The tip of the wall rivet retracts as the screw tightens, forcing out the two grippers and facilitating a firm grip against the inner surface.

* Special-purpose anchors include those designed to fasten perfboard, shelves and wire racks to the wall. These anchors incorporate spacers to hold material away from the wall with a configuration tailored to shelves and racks. Also available is a one-piece, all-steel screw anchor that is designed to go through drywall and penetrate wood and metal studs with no pre-drilling.

MASONRY ANCHORS

With the wide use of masonry in construction, the need for masonry anchors is important. Almost all homes have a garage, basement, patio or porch that requires some kind of masonry anchor.

The holding power of masonry anchors is determined by laboratory tests. Where the static load or shock load is excessive or where the customer does not knew the actual load, you should recommend using extra fasteners for secure anchorage.

* Concrete anchors are hardened steel screws that are designed to cut threads in pre-drilled holes. The holes can be drilled right through the item to be fastened without moving the fixture.

Concrete screws come in flat head, Phillips drive or hex-washer head styles. They work equally well in poured concrete, concrete block or masonry. The pull-out resistance of concrete screws is much greater than in plastic screw anchors as they bite directly into the concrete.

* Drop-in type anchors are expandable concrete anchors that are set in pre-drilled holes. They accept standard course thread bolts or threaded rod. Drop-in style anchors de not require patching after sinking. They come in sizes to fit bolt diameter 1/4"-3/4".

* Impact-expansion concrete anchors range in diameters from 1/4"-3/4" and lengths from 1-3/4"-6". The drill size is the same as the anchor diameter. Impact-expansion concrete anchors are stud-type anchors. Setting requires driving the center pin down to the top of the anchor, which expands the sides of the anchor against the walls of the hole. The hole can be drilled through the item to be fastened without moving the fixture. Impact-expansion concrete anchors come in plated hardened steel or stainless steel.

PLASTIC AND NYLON ANCHORS

Plastic and nylon anchors are accepted as all-purpose fasteners because they can be used in both hollow and solid wails and in almost all kinds of construction materials.

There are five basic types. Plastic anchors are used for mounting items such as pictures and shelf brackets. Nylon expansion anchors expand as the screw is tightened. Nylon drive anchors expand as the nail is driven. Neoprene sleeves are used for mounting window fans, hi-fi speakers and other high-vibration items. Vibration-proof polypropylene screw anchors grip the wail and expand as the screw is tightened.

All plastic and nylon anchors are installed by placing them into drilled holes sized according to the anchor's type and length.

SPECIALTY ANCHORS

* Hinge-lock hollow wall anchors consist of a stud bolt with a hinged locking device attached to the end. The hinged locking device is slightly longer on one side of the hinge than the other. When inserted through the wall, the longer end causes the locking device to turn parallel to the wall, locking it in place. Because of the design of this product, the hole can be drilled right through the item to be fastened without moving the fixture. This type of anchor comes in sizes 1/4" x 1-3/4" through 3/8" x 4-1/2".

* A rust-resistant toilet bowl anchor replaces the conventional nut, washer and finish cover that frequently can be removed only with the use of a hacksaw. The cap nut is high-strength pelypropylene with self-locking threads. The stud bolt is 1/4" x 1/4", which when used with the cap nut, allows enough grip range to anchor most toilet bowls without sawing off the stud.

LAG SCREW SHIELDS

Lag shields are used inside drilled holes to provide anchors in the hole for lag bolts as they are wrenched into the shield. As the screw enters the shield, the shield expands and grips the interior. Horizontal fins prevent the shield from turning in the hole while tapered ribs ease insertion and ensure against slips.

SELF-DRILLING ANCHORS

A self-drilling expandable anchor, also known as a serrated sleeve, has teeth to gouge out its own hole in masonry when driven by an air or electric hammer or a special hand driver. It comes in bolt sizes from 1/4"-7/8", sets flush with the masonry surface and generally requires no patching after sinking.

EXPANSION SHIELDS

Expansion or lead shields are used with lag and machine bolts. As the bolt is tightened, the cone draws up through a slotted sleeve and expands against the interior of the drilled hole with great force. Since these fasteners require no caulking, they are excellent anchors for heavy holding of "problem material," such as cement, cinder blocks, hollow tile and other concrete mixes. They require large holes, so a power drill and masonry bit must be used.

Shorter lengths are recommended for anchorage in good-grade concrete or where thickness limits the length. Long lengths are better for poorer-grade concrete where extra anchorage is required.

DRIVE ANCHORS

Drive anchors or split nails or bolts are made of high-strength spring steel or of aluminum with a stainless steel pin for use in hard materials. As they are driven into a hole, they are compressed and forced against the walls of the hole. They come in three head styles: round, countersunk and stud. The stud type provides temporary attachment of items that must later be removed.

WOOD, SHEET METAL AND LAG SCREW ANCHORS

Securing fixtures of light and medium weight to solid and hollow masonry and brick walls is best accomplished with lead sleeve anchors and tag shields made of zinc alloy. Lag anchors hold best when expanded in the mortar joint with anchor sides pressing against the brick.

LEAD MACHINE SCREW ANCHORS

These anchors secure medium-weight fixtures to solid concrete by tamping a lead sleeve over a zinc alloy cone that is internally threaded to receive a machine screw or bolt. Once tamped in place with a special setting tool, the anchor is ready to receive the screw or bolt used in securing the fixture.