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Encyclopedia of Fasteners & Hardware Items
Courtesy of FastenerMart.com
— SCREWS —
Acoustic Lag Screws
Also Called: Acoustic Lag Bolts, Acoustic Lag Anchors, Flat Hanger Screws, Spade Lag Screws
 Acoustic Lag Screws have sharp points, wood screw threads and a hole on the flat end. They can be driven with a driver tool, or installed using an adjustable wrench or pliers. They are ideal for tie-down and tie-wire applications. Commonly found in suspended ceiling installations, they can also be used for wire guiding and hanging pipe, fixtures and more.
Cabinet Screws
  Cabinet Screws have deep threads for improved holding power. The Square drive style features a small round washer head, while the Phillips Modified Truss head has an extra large washer, which provides an increased bearing surface. Measure length from under the head.
Cabinet to Wood Screws
 Use these deep threaded screws to securely attach cabinets and other items to wood and metal. Choose standard point for wood, and self drilling point when attaching to metal. Cabinet to Wood and Metal Screws are available in three colors plus zinc. Measure length from under the head.
Cap Screws
Also Called: Cap Screws, Hex Head Cap Screws, Hex Bolts, Machine Bolts
 Cap Screws are generally 1/4" and larger in diameter, and are often Hex head, although 12 Point Flange and Slotted Flat head styles are also available. Partially threaded screws are very common; fully threaded cap screws are also called Tap Bolts. For Hex and 12 Point Flange cap screws, measure length from under the head. For Flat heads, length includes head height.
Cap Screws, Fully Threaded
Also Called: Tap Bolts, Hex Bolts, Hex Head Cap Screws Fully Threaded, Machine Bolts
 Cap Screws are generally 1/4" and larger in diameter and have a Hex head. Fully threaded Cap Screws are also called Tap Bolts. Measure length from under the head.
Deck Screws
Also Called: Deckboard Countersunk Screws, Robertson Drive Screws (Square Drive only)
 Deck Screws are made with a thin shank and a self-countersinking head. Square Drive Screws are designed to eliminate cam-out (the tendency of the bit to slip out of the screw drive recess) and are also known as Robertson Drive Screws. Measure length from the top of the head to the tip.
Dowel Screws
 Dowel Screws are ideal for attaching wood pieces and joints end-to-end due to their design of wood screw threads at each end. Measure length from tip-to-tip.
Drywall Screws
  Drywall Screws are available in several specialized varieties, each with unique properties. In all cases, length includes head height.
Phillips Bugle Head screws are self countersinking and resist tearing the paper surface of the drywall material.
Square Drive Trim Head screws have a head diameter that is about 1/3 smaller than bugle head screws.
Sharp Point screws are used for attachment to metal studs--up to 20 gauge--and wood. Their sharp point easily pierces drywall.
High-Low Thread style screws exceed the holding power of standard drywall screws in wood due to their design of alternating high and low thread heights. They can also be used with metal studs up to 20 gauge.
Self Drilling Point screws are used to fasten to metal studs up to 12 gauge.
Flange Screws
Also Called: Hex Washer Frame Bolt
  Hex Flange Head Screws allow a greater distribution of the load due to their large bearing surface head design. Also use them with irregular and oversized holes. Measure the length from under the flange to the tip.
For higher torque driving and a smaller head, use 12 Point Flange Head Cap Screws, which can be driven using a standard 12-point socket. Measure length from under the head.
Serrated Hex Flange Head Screws feature a serrated bearing surface that provides a grip on the mating material as the screw is tightened to resist loosening. Length is measured from under the head.
Floorboard Screws
Also Called: Floor Board Screw
 The head design of Floorboard Screws provide a flush surface in countersunk holes. For this reason, they are perfect in floorboard fastening applications. Measure length from the top of the head to the tip.
Framing Screws
Also Called: Minis
 Use Framing Screws to fasten metal studs to floor and ceiling channels. Measure length from under the head.
Hanger Screws
Also Called: Hanger Bolts
 Hanger Screws have no head--instead they have wood screw threads on one end and machine screw threads on the other to accept a hex nut or coupling nut. Measure length from tip to tip.
Hinge and Drawer Slide Screws
  If you've been searching for the hard-to-find Euro Drawer Slide Screws, look no further! Ours are M5 x 13 mm with a 7.5 mm head, and are Nickel plated.
We also have #5 and #6 Phillips Flat and Oval head Hinge & Drawer Slide Screws in 1/2" and 5/8" lengths, and in Bright Brass, Nickel and Antique finishes.
K-Lath Screws
Also Called: Metal Lath Screws
  These screws are used to attach metal lath, wire lath and wood strips to steel framing. K-Lath Screws are available in self-drilling and needle point styles; both have a Phillips round washer head. Measure length from under the head to the tip.
Lag Screws
Also Called: Lag Bolts
 Lag Screws are made in larger diameters and longer lengths, and have superior gripping power when compared to ordinary wood screws. They are also used in masonry applications when combined with an expansion anchor or lead anchor. Use a large diameter washer, such as a fender washer, to distribute pressure over a wider area. Measure length from under the head to the tip.
Machine Screws
  Machine Screws, which are seldom--if ever--known by any other name, range in size from 0 (very small) to 14, and sometimes larger. They are available in a variety of drive and head styles, materials and platings; certain drive styles offer tamper resistance (see complete listing under Tamper Resistant Screws). For Binding, Button, Fillister, Hex, Hex Washer, Pan, Round and Truss heads, measure length from under the head. For Flat and Oval heads, length includes head height.
Metal to Wood Screws
Also Called: Pole Barn Screws
 The neo-bonded sealer washer, which is backed by a steel washer under the hex head, compresses as you tighten to create a weather-tight seal. That makes these screws perfect for metal to wood construction applications. Available in ten colors plus zinc, measure the length of Metal to Wood Screws from under the head.
Self Drilling Screws
Also Called: Teks, Drill Screws
 Self Drilling Screws are installed with a standard power driver...each screw drills its own hole, taps its own threads, and then fastens the material...all in a single operation. Frequently used with sheet metal as well as stainless steel, aluminum, brass and plastic. Threads are coarse. Length is measured from under the head for Hex, Hex Washer, and Pan head styles. For Flat Wafer Head, length measurement includes head.
Self Sealing Self Drilling Screws
Also Called: Teks, Drill Screws, Self Sealing Screws
 Self Sealing Self Drilling Screws are installed with a standard power driver...each screw drills its own hole, taps its own threads, fastens the material, and seals the penetration...all in a single operation. Frequently used with sheet metal as well as stainless steel, aluminum, brass and plastic. Threads are coarse. Length is measured from under the head.
Sems Screws
Also Called: Machine Screws with Lock Washers
  Sems are machine screws with free-turning captive lock washers--external tooth and internal tooth lock washers are common. The screw/washer assembly saves time when compared to using individual screws and washers. Internal Sems, which have an internal tooth lock washer, are preferred when it is desirable to hide the teeth. The larger radius of an External Sems, though, provides greater locking action. Length is measured from under the head.
Set Screws
  Set Screws are used for locating and fastening knobs, gears, collars and other devices onto shafts. Standard point styles include Cone, Half Dog, Flat, Oval, Cup and Self Locking. In all cases, measure length from end to end.
The application itself typically determines which point style is appropriate. Considerations in selection include the materials involved, their relative hardness, how often the assembly is adjusted or disassembled and other factors. Standard point types are listed below along with their general attributes and typical applications. Some Set Screws use a nylon patch, which is bonded to the threads, or a pellet inset within the threaded area, to help prevent vibration-induced loosening.
For permanent location of collars, gears and pulleys on shafts, use Knurled Point Hex Socket Set Screws. They resist loosening and can tolerate severe vibration due to their counterclockwise locking knurls, which create a ratchet action. They perform well even in poorly tapped holes.
When working with soft materials, where high-tightening torques are not practical, and with hardened shafts too, consider using Cup Point Hex Socket Set Screws. The edge of the cup point digs into the mating surface to prevent slippage.
Flat Point Hex Socket Set Screws are used where parts must be adjusted or relocated often because their points cause little or no damage when tightened. They can be used against hardened shafts--especially shafts with flats for greater contact area--and are excellent with thin walled materials and on soft plugs.
Oval Point Hex Socket Set Screws, or Round or Crowned point as they are sometimes called, are used with angled surfaces and in applications requiring frequent adjustment with little or no damage to the part they bear against. Use with a circular "U" shaft groove when rotational adjustment is needed or with an axial "V" groove for longitudinal adjustment.
A sharp cone tip gives Cone Point Hex Socket Set Screws the greatest axial and torsional holding power because of deep penetration. For this reason they are used for permanent location of parts, as pivots and where fine adjustment is needed.
Half Dog Point Hex Socket Set Screws often replace dowel pins and are used for permanent location of one part to another. The cylinder point locks in a hole drilled in a shaft or against a shaft flat. They work well against hollow tubing and hardened members.
Sheet Metal Screws
Also Called: Tapping Screws, Type A Screws, Type AB Screws
  Sheet Metal Screws are used in situations where the material is too thin to tap--like sheet metal--and you don't have rear access to install a nut, but you may need to unfasten the materials later. They have spaced (coarse) threads, and are also used in wood. For Button, Hex, Hex Washer, Pan, Round and Truss heads, measure length from under the head. For Flat and Oval heads, length includes head height. Certain head styles offer tamper resistance (see complete listing under Tamper Resistant Screws).
Shoulder Screws
Also Called: Stripper Bolts
 Shoulder Screws have a cylindrical head, a smooth cylindrical shoulder and a short threaded section. A small area between the threads and shoulder is undercut, which allows for a tight fit against a mating surface. Used as a bearing or spacer, their applications number many: as shafts for cam rolls and other rotating parts, as pivots and stud bolts, and as bearing pins for swing arms, links and levers. Often combined with bronze sleeve (Oilite) bearings, they are also used as a guide in blanking and forming presses and in punch and die operations.
Size is specified as Shoulder Diameter (inches) x Shoulder Length (inches) x Thread Diameter (number or inches) - Threads per Inch. Hex Key size is half of Shoulder Diameter--for 1/4 Shoulder Diameter, use a 1/8 Hex Key; for 5/16 use a 5/32 Key; for 3/8 use a 3/16 Key; for 1/2 use a 1/4 Key; for 5/8 use a 5/16 Key; for 3/4 use a 3/8 Key; and for 1 use a 1/2 Key.
Socket Cap Screws
  Hex and Torx drive Socket Cap Screws are often found in applications where there is insufficient wrench/socket clearance for hex head cap screws, or when a "finished" look is desired. Button heads provide a larger bearing surface and a lower head profile than Socket heads, and are used when the material is too thin to countersink. Because of their smaller outer diameter, Socket Head screws may be preferred and are sometimes recessed (counterbored). When clearance is an issue, use a Low Socket Head instead of a Socket Head. Socket Head screws are recommended for high strength applications; Button and Flat heads are suggested when only moderate strength is needed. Reusable Self Locking screws rely on either a nylon patch, which is bonded to the threads, or a pellet inset within the threaded area, to help prevent vibration-induced loosening. For Button and Socket heads, measure length from under the head. For Flat heads, length includes head height.
Tamper Resistant Screws
Also Called: Tamper Proof Screws, Spanner Head Screws, One Way Screws, Pin Hex Head Screws, Pin Torx Head Screws
  The drive style of these machine screws and sheet metal screws resist tampering: Spanner, One Way, Pin Hex and Pin Torx. Install One Way screws using a regular flat blade (slotted) screwdriver; removal requires a special tool. Spanner, Pin Hex and Pin Torx require special tools. Measure length of Button, Pan, Round and Truss Tamper Resistant Screws from under head. Length of Flat and Oval heads include height of head.
Tap Bolts
Also Called: Tap Bolts, Hex Bolts, Hex Head Cap Screws Fully Threaded, Machine Bolts
Cap Screws are generally 1/4" and larger in diameter and have a Hex head. Fully threaded Cap Screws are also called Tap Bolts. Measure length from under the head.
Thread Cutting Screws
Also Called: Tapping Screws, Thread Cutting Screws, Type F Screws
  These screws have a blunt point and tapered starting threads. Cutting flutes at the tip act like a tap to create machine screw mating threads in a pre-drilled or punched hole as they are installed. Thread Cutting Screws can be removed and reinserted or replaced by a machine screw of the same diameter and number of threads per inch. For Hex Washer, Pan and Round heads, measure length from under the head. Length includes head height for Flat Head.
Thread Rolling Screws
Also Called: Tapping Screws, Thread Forming Screws, Trilobe Thread Rolling Screws
  Thread Rolling Screws are a member of the self tapping screw family. The three lobes form threads in a punched or drilled pilot hole without producing any chips. Low drive torque is needed, and the fastened joint resists loosening caused by vibration.
Thumb Screws
Also Called: Spade Head Screws, Type P Screws, Type S Screws
  Thumb Screws, like Wing Nuts, are made to be tightened and loosened with finger pressure and are typically used where frequent adjustment or disassembly is required. They are fully threaded. Length of Spade Head (Type P) screws is measured from under the head to the tip. Spade Head with Shoulder (Type S) screws are measured from under the shoulder to the tip. The shoulder adds a bearing surface.
Trim Screws
Also Called: Oval Head Phillips Screws, Small Countersunk Screws
 These are Phillips Oval Head Sheet Metal Screws but with undersized heads--a #10 screw with a #6 head, for example. Measure the length of Trim Screws from the top of the head to the tip.
Type U Drive Screws
 Type U Metallic Drive Screws have multiple, very coarse threads and a blunt point. These screws are forced under pressure into the material to be fastened. Once installed, Drive Screws are considered permanent.
Washer Trim Screws
Also Called: Sems Trim Screws, Oval Head Phillips with Countersunk Washer
These screws are manufactured with an integral countersunk finish washer. The washer is retrained by rolled threads under the head, yet rotation of the head separate from the washer is allowed during tightening. The oval head and countersunk washer protrude slightly above the material surface. The pre-assembled design of these screws simplifies installation while providing a finished appearance. Measure the length of Trim Screws from the top of the head to the tip.
Wood Screws
  Wood Screws have a sharp point and a special thread design that allows them to bite into wood. Threads cover about 66% of the screw length. Measure length from under the head for Round Head. For Flat and Oval heads, length includes head height.
Wood to Metal Screws
Also Called: Teks, Reamer Screws
  These screws are designed to drill into wood, then metal. First the wings drill a clearance hole through the wood, allowing the threaded section to follow without obstruction. Then the drill point drills through the metal, which the screw threads into, thus fastening the assembly. When completed, the flat screw heads are flush with the surface. Wood to Metal Screws are ideal for fastening plywood or similar material to metal. Measure length from the top of the screw to the tip.
Woodie Screws
Also Called: Deck Screws
 Use these screws for finish and trim work. The auger point is self drilling, and the nibbed head reams the wood and countersinks the head. Woodie Screws are available in combination, square, and Phillips drive styles. Use the All Weather version when rust resistance is needed. Measured length includes the Flat Head height.
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