螺丝分类命名及编码

常用螺丝头型、槽型、牙型图岗山头（B头）平头（K头）C头含华司台阶圆头含华丝（PWM）六角含华司（HWM）外六角头梅花一字槽圆头（P头）梅花一字槽美国P头O头盘圆含华司伞头含华司（TWM）T头伞头含华司尖尾（TWA）圆头含华司一字梅花槽圆头三角牙（STP）十字槽加减槽一字槽内三角槽内六角槽梅花一字槽A牙B牙M牙STB牙ST牙B牙B双牙T牙MACHINE SCREWSDescription MATERIAL SIZESPan Head Combination Machine ScrewZincPlatedSteel4-40x1/8 thru1/4-20x4Round Head Combination Machine ScrewZincPlatedSteel6-32x2 thru1/4-20x4Truss Head Combination Machine ScrewZincPlatedSteel6-32 thru 1/4-20Flat HeadPhillips Machine ScrewZincPlatedSteel2-56x1/8 thru1/2-13UndercutFlat HeadPhillips Machine ScrewZincPlatedSteel2-56x1/8 thru3/8-16Flat Head100°Phillips Machine ScrewZincPlatedSteel2-56x1/8 thru1/4-20x1-1/2Fillister Head Phillips Machine ScrewZincPlatedSteel2-56x1/8 thru5/16-18x2Oval HeadPhillips Machine ScrewZincPlatedSteel4-40x1/4 thru1/4-20x3Pan HeadPhillips Machine ScrewZincPlatedSteel2-56x1/8 thru3/8-16x3Round HeadPhillips Machine ScrewZincPlatedSteel2-56x1/4 thru3/8-16Truss HeadPhillips Machine ScrewZincPlatedSteel4-40x3/16 thru3/8-16x2-1/4Indented Hex Washer HeadPhillips Machine ScrewZincPlatedSteel4-40x1/4 thru1/4-20x1Binding Undercut Slotted Head Machine ScrewZincPlatedSteel2-56x1/8 thru1/4-20x1-1/4Flat HeadSlotted Machine ScrewZincPlatedSteel2-56x1/8 thru1/2-13x6UndercutFlat HeadSlotted Machine ScrewZincPlatedSteel2-56x1/8 thru3/8-16x1/2Fillister Head Slotted Machine ScrewZincPlatedSteel2-56x1/8 thru3/8-16x1-1/4Oval HeadSlotted Machine ScrewZincPlatedSteel4-40x1/4 thru1/4-20x2Pan HeadSlotted Machine ScrewZincPlatedSteel2-56x1/8 thru3/8-16x3Round HeadSlotted Machine ScrewZincPlatedSteel2-56x1/8 thru1/2-13x6Truss HeadSlotted Machine ScrewZincPlatedSteel4-40x1/4 thru1/2-13IndentedHex HeadSlotted Machine ScrewZincPlatedSteel4-40x1/4 thru3/8-16IndentedHex HeadUnslotted Machine ScrewZincPlatedSteel4-40x1/4 thru3/8-16IndentedHex WasherSlotted Grounding ScrewGreenZincPlatedSteel10-32x3/8 and10-32x1/2IndentedHex WasherSlotted Grounding ScrewZincPlatedSteel4-40x1/4 thru3/8-16x2-1/2Indented Hex WasherSlotted Machine ScrewZincPlatedSteel4-40x1/4 thru3/8-16x2-1/2Indented Hex WasherUnslotted Machine ScrewZincPlatedSteel4-40x1/4 thru3/8-16x2Flat Head Torx® Drive Machine ScrewZincPlatedSteel4-40x1/4 thru1/4-20x2Pan Head Torx® Drive Machine ScrewZincPlatedSteel2-56x3/16 thru1/4-20x2Pan HeadPhillips Shakeproof®Square Cone® Washer Sems MachineScrew Screw isZincPlatedSteelBakedAfterPlating4-40x1/4 thru10-32x3/4Pan HeadPhillips Split LockWasher Sems MachineScrew Screw isZincPlatedSteelBakedAfterPlating4-40x1/4 thru1/4-20Pan HeadPhillips External Sems Machine Screw Screw isZincPlatedSteelBakedAfterPlating4-40x3/16 thru1/4-20x1-1/4Pan HeadPhillips Internal Sems Machine Screw Screw isZincPlatedSteel23-56x1/8 thru1/4-20x1Baked After PlatingPan HeadSlotted External Sems Machine Screw Screw isZincPlatedSteelBakedAfterPlating4-40x3/16 thru1/4-20x1-1/4Pan HeadSlotted Internal Sems Machine Screw Screw isZincPlatedSteelBakedAfterPlating4-40x1/4 thru10-32x1Flat HeadPhillips Machine ScrewBlackOxidePlatedSteel2-56x1/8 thru1/4-20x2Pan HeadPhillips Machine ScrewBlackOxidePlatedSteel2-56x1/8 thru1/4-20x2Types of Screw HeadsPAN HEAD: Recommended for newdesigns to replace round, truss and bindingheads. Provides a low large diameter head, butwith characteristically high outer edge alongthe-outer periphery of the head where drivingaction is most effective for high tightening'torques. Slightly different head contour wheresupplied with recessed head.FLAT HEAD: Supplied to standarddimensions with an 80' to 82' angle to be usedwhere finished surfaces require a flush fasteningunit. The countersunk portion offers goodcentering possibilities.ROUND HEAD: Not recommended for newdesign (see pan head). This head was the mostuniversally used design in the past.OVAL HEAD: Fully specified as "ovalcountersunk", this head is identical to thestandard flat head. but possesses. in addition, arounded, neat appearing upper surface forattractiveness of design.FILLISTER HEAD: The-standard oval fillister head has a smaller diameter than the round head. but is higher with a correspondingly deeper slot. The smaller diameter head increases the pressure applied on the smaller area and can be assembled close to flanges and raised surfaces. Headed in counter bored dies to Insure concentricity, they may be used successfully in counter bored holes. BINDING HEAD (Straight Side): Most generally used in electrical and radio work because of its identifying undercut beneath the head, which binds and eliminates fraying of stranded wire. Offers an attractively designed, medium-low head with ordinarily sufficient bearing surface. 'Not ordinarily recommended as a Phillips Recessed head-see Pan Head for better functional design.TRUSS HEAD: Also known as oven head, stove head, and oval binding head. A low, neat appearing, large diameter head having excellent design qualities, and as illustrated can be used to cover larger diameter clearance holes in sheet metal when additional play In assembly tolerance is required. Suggest pan head as a substitute.HOLT HEAD (PATENTED): Provides the perfect tamper-proof assembly. Theft-proof-decorative, yet inexpensive. Special drivers available for field removal or power driven assembly machines.ONE-WAY HEAD: This ingenious, tamper-proof type of head, once assembled cannot be removed. yet is driven with a standard screw driver. Manufactured with amazing economy in productive quantities, this, simple design can frequently solve costly assembly problem.PHILIPS FINISHING WASHER HEAD: Designed as a neat appearance product for the electronic and appliance trade with all threaded styles.WASHER HEAD: This design has the finished appearance of a conventional round head plus washer and was originality created to provide extra large bearing surface under the head. The modern "truss" head (carried in stock) normally answers this purpose. When a. larger diameter is required this washer head is recommended.FLAT AND OVAL HEADS (UNDERCUTI: This Is the standard flat or oval head SO' to 82' countersunk screw which has the lower one-third of the countersunk portion removed to facilitate production of extremely short lengths. As Illustrated, it will fit a standard counterbored hole and Is particularly adaptable to flush assemblies in thin stock.FLAT HEAD (100' COUNTERSUNK): This special flat head screw has been developed for applications requiring flush surfaces, and is recommended for use In soft materials. to distribute pressure over a larger and less angular surface. Very well adapted for use with thin aluminum, soft plastics, etc.SQUARE SHOULDER SCREWS:An adaptation of the standard carriage boltdesign.Possesses a truss head on a square shankwhich resists rotation when located or, driveninto place. This square shoulder may also bestaked Into place as a permanent fastener. Agreat many varieties in all screw diameters areavailable in productive quantities.Flat Head styles take full advantage of theself-centering feature of the countersunk portionand provide a smooth, flush outer surface.Type "T" (Overlug) For applicationsrequiring smooth, finished outer surfaces. Undersurface of head is designed for perfect electrodecontact.INDENTED HEXAGON: An inexpensivewrench head fastener made to standardhexagon head dimensions. The hex Iscompletely cold upset in a counterbored die andpossesses an Identifying depression In the topsurface of the head.INDENTED HEXAGON WASHERHEAD: Produced in the same manner as thestandard Indented hexagon head but with awasher section at the base of the head to protectthe finish of the assembly from wrenchdisfigurement.ACORN HEAD (FULL UNDERCUTI: Avery neat appearing trim screw for applianceapplication-excellent wrench surfaces.HEXAGON HEAD (TRIMMED): This isthe standard type of wrench-applied hexagonhead, characterized by clean, sharp cornerstrimmed to close tolerances. Recommended forgeneral applications. It Is available In allstandard patterns and In all thread diameters.HEAD STYLES (WELDING SCREWS):The welding screw has been developed toprovide a strong permanent threaded fastenerwhich becomes an Integral part of the assembly.It utilizes the principle of projection welding bymeans of multiple lugs applied to various headsurfaces.Type "U" (Underlug) for general application.Assembles easily into pre-located holes and fullyutilizes head strength. Top surfaces of headdesigned for efficient welding anode contact. STAINLESS STEEL WASHERSDESCRIPTION MATERIAL SIZESStandard Flat Washers18-8StainlessSteel1/4 thru1.0Standard Flat Washers316StainlessSteel1/4 thru1.0Fender Washers18-8StainlessSteel#10x11/16thru1/2x2Machine Screw Washers18-8StainlessSteel#2 thru#10Medium Split Lock Washers18-8StainlessSteel#2 thru1.00External ToothLock Washers410StainlessSteel#4 thru3/8Internal ToothLock Washers410StainlessSteel#2 thru3/8METRIC NUTSDIN SPEC CLASS MATERIAL SIZES934Class6Style1Zinc Plated Steel Nut*M2 &M3934Class8Style1Zinc Plated Steel Nut*M4thruM20934Class10Style1Zinc Plated Steel NutM6thruM20934Class10Plain Steel NutM6thruM20985Class8Zinc Plated SteelNylon Insert Lock NutM3thruM20* M4 and smaller nuts do not require class marking。