QUICK SELECTION GUIDE - Unbrako

1 QUICK SELECTION GUIDE3 QUICK SELECTION GUIDETypeApplicationFeatures2 Suitable for all high tensile applications. Use stainless for corrosive-cryogenic or elevated for use in parts too thin for std. SHCS; and for applications with angle under the head ensures maximum flushness and sidewall contact. Non-slip Hex socket prevents marring of : Inclined angle under the head varies as follows:BSW & BSF Threads - 90 CUNC & UNF Threads - 82 CMetric Threads- 90 CAbove M20- 60 CLow heads streamline design. Use them in materials too thin to countersink: also for non-critical loading requiring heat treated costly special parts - shafts, pivots, pins, guides, linkages and trunnion mountings. Also standard for tool and die collars, sleeves, gears, knobs on shafts. Locate machine partsCone, half dog, oval, cup and self locking knurled cup points are Head Cap ScrewsAlloy SteelStainless SteelStainless SteelSocket Low Head Cap ScrewCountersunk Socket Head ScrewsButton Head ScrewsShoulder ScrewsAlloy SteelAlloy SteelAlloy SteelAlloy SteelStainless SteelStainless SteelSocket Set ScrewsAlloy SteelMaximumOperatingMaterialCorrosionMa gnetic orPageTemperatureResistanceNon-MagneticU nplatedHigh GradePlating300 CUnbrakoOptionalMagneticAlloy Steel4 to 18 Austenitic 430 CStainless ExcellentNon-MagneticSteelHigh GradePlating 300 CUnbrakoOptionalMagnetic11 Alloy SteelHigh GradePlating300 CUnbrakoOptionalMagneticAlloy Steel19 to 26 Austenitic430 CStainlessExcellentNon-MagneticSteelHigh GradePlating300 CUnbrakoOptionalMagneticAlloy Steel27 to 30 Austenitic430 CStainlessExcellentNon-MagneticSteelHigh Grade300 CUnbrakoFairMagnetic41 to 44 Alloy SteelHigh GradePlating300

2 CUnbrakoOptionalMagneticAlloy Steel31 to 39 Austenitic430 CStainlessExcellentNon-MagneticSteelUNBR AKO DEVELOPMENTS MEAN - Extra Strength Where If Counts5 SOCKET HEAD CAP SCREWS4 YOU RE SAFER WITH Unbrako Deep, accurate socket for uniform wrenching power and highmaximum torques. Precise knurls for easier handling and forged head for continuous grain flow and maximum head to shank fillet for increased fatigue runout increases fatigue THREADRUNOUT Note sharp angle atroot where high stressconcentration can developcracks in the RADIUSED ROOTRUNOUT THREAD - Controlledradius of runout root provides asmooth form that distributesstress and increases fatigue lifeof fastener formed radiused threads rolled to maintain continuous grain flow for greater tensile and fatigue treatment in a controlled atmosphere for maximum uniformstrength and surface integrity without brittleness or control of socket depthgives more wrench engagementthan other screws, permitting fulltightening without cracking orreaming the socket, yet maintainingample metal in the crucial fillet areafor maximum head head forging formsuniform grain flow with unbroken flow lines.

3 Makes heads stronger,prevents failure in vital fillet area and adds to fatigue strength of the of radiused fully formedthreads. Contour following flow linesprovide extra shear strength inthreads, resist stripping and providehigh fatigue resistance. Note the largeroot radius, an Unbrako socket screwdevelopment that increases fatigue lifeof the you use fasteners, you know their importance in today stechnology. Higher pressures, higher stresses and higherspeeds demand stronger, more reliable joints, andstronger, more reliable fasteners to hold them must stay together. A single failure can destroyvaluable equipment or stop an assembly line. Reliabilitymust be is why industry is using more and more sockethead cap screws, the strongest threaded fasteners you buy off the shelf . They have the extra strength and fatigueresistance required for total reliability in high and Fatigue StrengthUnbrako socket head cap screws have the highest levelsof strength and fatigue resistance in the industry.

4 Theyexceed all government and industry standards. Instead ofthe usual range of 1220 N/mm2, minimum tensile strengthlevels of Unbrako cap screws are consistently 1300 the same time ductility and fatigue resistance are you buy tension fasteners (which is what sockethead cap screws basically are) you re buying clampingforce - the ability to hold things together. The additionalstrength offered by Unbrako screws can save pounds, ifyou use the screws extra strength of Unbrako screws allows the use ofeither fewer fasteners of the same size, or the samenumber of smaller screws to achieve the same clampingforce. With fewer fasteners you save on drilling and tappingand have fewer screws to buy and install. If you go theother way, smaller screws generally cost less and permitreduced assembly size, saving space, material and you have dynamic stress or varying load conditions,the exceptional fatigue resistance of Unbrako screws givesyou an additional bonus of built-in protection againstfatigue of three major factors in the superiority of Unbrakosocket head screws is design.

5 For example, socket depthis carefully controlled. The socket is deep enough for fulltightening without reaming and cracking, but not deepenough to weaken the head area and cause by our research and development of aerospacefasteners, another major feature on Unbrako socketscrews is the Radiused-Root-Runout. The root of thethread runout is also radiused to eliminate the usual sharp V - a major point of weakness in other threads. Fatigue life in this critical area is increased as much as 300% incertain 4g 6g tolerances are standard, the closest withoutselective assembly. They combine maximum cross-sectionwith smooth assembly, and assure better mating of elliptical fillet at the juncture of head and shank isanother aerospace-inspired Unbrako development. Thiscompound curve more than doubles fatigue life in the headarea without reduction of critical bearing area.

6 Discontinuityis minimised and stress concentrations are reduced,providing an added margin of safety. Heads are correctlyproportioned to screw size, assuring full clamping forcewithout indentation and loss of major factor in Unbrako socket screw superiority is their physical properties. These are no higher stress levels area direct result ofcustomised heat treatment. Carbon content of furnaceatmospheres is closely controlled, since carburisation (toomuch carbon) makes screws brittle, while decarburisation(too little carbon) results in soft surface with poor strengthand resistance to wear. Every melt of Unbrako steel is pre-tested and its treatment tailored to produce a consistent ControlClosely controlled manufacturing is the third factor. Rigidcontrol of every operation of a socket screw is necessary inorder to guarantee of standard Unbrako socket screws are forged,not machined.

7 Machining cuts metal fibres, breaks flowlines, creates planes of weakness at stress points. Forging,on the other hand, forms metal, produces uniform grainflow, makes heads stronger by compressing the bearing area is strictly perpendicular to screw bodyto avoid strains and misalignment. Fillet areas are preciselycontrolled, with fillets made glass smooth to eliminatesurface irregularities where cracks can threads of standard Unbrako screws are rolled,not ground or cut. Rolled threads are more uniform andcloser tolerances can be maintained because SPS threadroll dies and rolling techniques produce smoother surfacesand more accurate size control. High points and planes ofweakness are becomes more critical as the demand for platedscrews increases. Unbrako socket screws that are to beplated are accurately controlled to be within tolerance afterplating.

8 Precision plating thickness brings screws to correctdimensions, while rigid control of the plating processguards against screw failure from hydrogen is a brittle condition caused by hydrogen diffusing intothe base material during cleaning and electroplating. It cancause screw failure long after the screw is tightened, butcan be avoided by the extreme care Unbrako take inprocessing plated socket Socket Screws pay off in SavingsYou get extra safety and reliability in Unbrako socketscrews, plus significant economies, both in the cost of thefasteners and the cost of their installation. Furthermore,they protect the reputation of your product, which can welldepend on the fasteners that hold it are considerations too important to overlook as production costs continue to rise and reliabilityrequirements become more HEAD CAP SCREWS - ISO Metric7 APPLICATIONS6 FEWER HOLES TO DRILL AND TAPOld Method5 - M10 Screws @ 800 N/mm2tensile640 N/mm2yield = 5 x 640 x 58 =186 kN max.

9 LoadUnbrako Method3 - M10 Screws @ 1300 N/mm2tensile1170 N/mm2yield = 3 x 1170 x 58 =204 kN max. loadOld Method12 - M16 Hexagon Head Screws @ 800 N/mm2tensile strengthTotal strength = 1206 kNUnbrako Method16 - M16 Socket HeadCap Screws@ 1300 N/mm2tensile strengthTotal strength = 2940 kNOld Method800 N/mm2M12 Bolt tensile = 67 kN yield = 54 kNUnbrako Method1300 N/mm2M12 Unbrako Bolttensile = 110 kN yield = 99 kNExtra Unbrako Joint Strength:tensile = 64% Increaseyield = 83% IncreaseOld Method800 N/mm2M12 BoltShear Strength = 40 kNExample(shown above) - against adjacent machine partsUnbrako Screw requires 50% less space for clearance. In counterbored screw application Unbrako Screws requireminimum counterbore since no wrench clearance is Method1300 N/mm2M12 Unbrako BoltShear Strength = 66 kNExtra Unbrako ShearStrength = 26 kN lesswrenching space neededOrdinary BoltsSocket Head CapScrewsOrdinary BoltsSocket Head CapScrewsCOMPACT SPACINGHIGH TENSILE AND YIELD STRENGTHHIGH SHEAR STRENGTHT hree screws do the work of fiveClearance for socket wrenchNo wrench clearance necessaryDIMENSIONS AND tightening TORQUES - ISO Metric ThreadsApplicable or Similar Specifications:Product BS 4168 DIN 912 ISO 4762 GradeBS 6104 Grade 898/1 Grade for M5 diameter and largerThread SizeThreadSize (B Max.)

10 PitchA Max. da Max. H NOTE 2 LLength of ThreadT (Ref)Maximum tightening TorquesUnplatedPlated Induced (M14) (M18) (M22) 198000 See Note 1 and Grip Lengths are shown on Pages 8 & 9. with lengths equal or shorter than listed in column L will be threaded to Thread Class:4g6g4. da:Transition Diameter5. Working Temperature:-50 C+300 calculated in accordance with VDI 2230 Systematiccalculation of high duty bolted joints with = 1080 N/mm2and = for plain finish and = for DIMENSIONS IN MILLIMETRES. SIZES IN BRACKETS ARE NON-PREFERRED PROPERTIESM aterialUnbrako High Grade Alloy SteelHeat TreatmentRc 40-43 Screw Size M16>M16 Tensile Strength1300 N/mm21250 N/mm2 Yield Strength1170 N/mm21124 N/mm2 Shear Strength780 N/mm2750 N/mm2 Min. Elongation9%9%SOCKET HEAD CAP SCREWS - ISO Metric8 SOCKET HEAD CAP SCREWS - ISO Metric9 BODY AND GRIP LENGTHS - ISO Metric ThreadsThreadSizeBody and GripLengths202530354045505560657080M3LB.