bearing types and details of construction nhbb astro division produces a variety of sliding surface bearings the construction and material selection of each varies depending on factors such as load temperature hardness and dimensional limitations nhbb engineers are also pleased to discuss the design and manufacture of special bearing designs for a discussion of the available liner and lubrication systems see pages 59-60 and 66-67 respectively v-groove type swaged bearings the primary product of nhbb astro division is the swaged spherical bearing this bearing is manufactured by swaging a ductile race around a hardened ball the race is machined and the assembly loosened released to obtain proper clearance or torque or both and then ground to finished size swaged sphericals normally feature 80 to 100 contact between the race i.d and the ball o.d the large contact area between ball and race allows the all-metal bearing to take very high static loads and beryllium copper and teflon® lined b
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track rollers nhbb manufactures track rollers see 15 and 16 as an alternative to needle roller bearings the teflon® composite track roller can be designed to existing needle roller envelope dimensions the track roller is made up of an outer member roller which slides over an inner member bushing or stud and these two members sandwich a low friction low wearing teflon® composite material the inner and outer members are retained in the axial direction by thrust washers that are either press fit staked or welded onto the inner member to support axial loading design features of nhbb s track rollers are high load carrying capability resistance to many corrosive chemicals and environmental contaminants and the ability to absorb heavy vibratory loads sliding surface track rollers offer improved bearing performance over needle rollers with respect to these design features while this product may be utilized in many rolling applications it is not recommended for high rotational speeds or where
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ad ak and k liner systems duraliners nhbb s ad ak and k liner systems consist of teflon® nomex® and a thermosetting phenolic resin the ad ak and k liners are suitable for many fixed wing aircraft applications such as actuators hinges and control bearings where oscillation angles vary considerably but at slow oscillation speeds the ad ak and k liners are qualified to as81820 and as81934 to qualify to as81820 a lined bearing will be tested at room temperature for 25,000 cycles of ±25 degrees at 10 cpm and at 37500 psi maximum allowable wear is 0.0045 when tested at elevated temperature requirement the allowable wear is 0.006 when tested at -65°f the load is reduced to 75 of the room temperature requirement and the allowable wear is 0.008 as81820 also has a test requirement for bearings to be immersed in various fluids for 24 hours at 160°f removed from the fluid and dynamically tested at 75 of the room temperature load requirement nhbb s ad ak and k liners consistently exhibit less wear
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factors affecting the selection performance and evaluation of teflon® lined spherical rod end and sleeve bearings an answer to situations where the performance envelope cannot be covered by metal-to-metal bearings is to consider teflon® lined bearings here the lubricant configuration is such that it functions as the load carrying element of the bearing as represented by the liner systems currently in use teflon® bearings may be specified under all or some of the following situations 1 where lubrication is undesirable difficult to perform or impossible 2 where loads are high and angular movement is low 3 where space is limited 4 where vibration is present 5 where temperature of the environment renders greasing unfeasible 6 where a joint must remain static for an extended period of time before movement is initiated 7 where friction in a greased bearing would be so high as to render the joint area useless after a limited number of cycles or impose an unacceptable fatigue situation 8 where
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nas 513 key thread size d 005 000 .056 .056 .056 .069 .069 .077 .077 .077 .086 .094 .094 .116 .116 .116 .129 .129 .129 .129 .129 .129 dd 005 000 .110 .110 .110 .110 .110 .125 .125 .156 .156 e 005 000 .062 .062 .093 .093 .093 .125 .125 .125 .156 .156 .187 .187 .250 .250 .250 .312 .312 .312 .312 .312 f 000 005 .201 .260 .311 .370 .436 .478 .541 .663 .777 .900 1.010 1.136 1.236 1.361 1.477 1.589 1.714 1.839 1.955 2.080 .250 nas 513 key nas 509 nut .312 .375 .437 .500 .562 rod .625 rod end .750 .875 1.000 1.125 dd optional d e 2 1.250 2 slots only required for thread sizes .250 .312 .375 1.375 1.500 .005 r .015 f 1.625 1.750 1.875 e typ .015 r .005 typ e 2.000 2.125 35 notes female keyslot 36 2.250 male keyway nas 513 key · 1 nas 513 keys are used on as81935 sizes -10 through -16 rod ends when optioned the keyways and keyslots used in conjunction with these keys are shown in 35 and 36 · for female rod ends with deep square slot keyslot option as81935 designat
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engineering bearing installation and retention housings the housing into which the bearing is mounted must be designed to ensure the structural integrity of the bearing the recommended housing dimensions are as follows 1 bearing-to-housing fit .0002 tight to .0008 loose 2 bore finish 32 ra 3 round within the bore diametral tolerance 4 bore aligned perpendicular to housing faces within .002 for sleeve bearings only 5 housing width .005 tolerance for staking purposes 6 for v-groove retention the housing bore is chamfered chamfer size is calculated as shown in 39 page 71 7 for housing stake and bolted plated retention break edges .005 max on both sides the recommended shaft and housing sizes are based on an operating temperature range of -65° to 350°f at elevated temperatures allowances must be made for different coefficients of expansion for the various shaft bearing and housing materials in general the mating components should be adjusted to provide the recommended fit at operating te
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engineering bearing installation and retention v-groove staking tool the staking tool and staking anvil depicted in 49 and 50 are made from tough hardenable tool steel for example a-2 and heat treated to rc55 to 60 the critical dimension of the tools are as listed as a final check on the staking tool and anvil a final layout drawing should be made to check fit-up nhbb manufactures staking tools to meet many customers needs to obtain staking tools specially manufactured by nhbb please refer to ordering information on page 77 .001 d 8 .001 d .010 .005 r continuous -d b 25° 21° c 0 .001 d a pin diameter 0 .001 d 49 staking tool design a ball bore min .001 tolerance .000 .001 b bearing o.d 2 x min lip thickness min groove width tolerance .005 .000 see 46 for lip thickness page 75 s and groove width x c adequate stakes for most applications are obtained with staking tools having 45° to 50° outside angles when required secondary staking tools having an outside angle of 60° t
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engineering load ratings and misalignment capabilities load ratings the load rating of a bearing is determined by the dimensions and strength of its weakest component external factors such as mounting components pins bolts and housings are not considered part of a bearing when load ratings are investigated but should be considered separately spherical bearing load ratings the weakest part or load-limiting area of a spherical bearing is its race for this reason formulas have been developed that use the race to calculate static load ratings based on size and material strength the static load rating formulas for self-lubricating and metal-to-metal spherical bearings are shown in 57 and 58 these formulas will yield approximate ratings which should be used as ballpark numbers for bearing design the allowable radial stress values given in the tables were determined from the ultimate tensile strength specifications for various race materials allowable axial stress values were derived from ma
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engineering bearing selection factors rolling element bearings 1 low load high speed bearings should usually be antifriction rolling element bearings except for lubricated sleeve bearings under very low load and constant rotation rather than oscillatory 8 special types of metal-to-metal sphericals such as loader slot bearings fractured outer race bearings or snapassembled bearings page 54 and 55 are used for some applications where very hard inner and outer races are desirable for wear and strength reasons but require special geometry a relatively narrow ball 9 spherical and rod end bearings for both high temperature and cryogenic applications are available using special materials such as the inconels® stellite® and other cobalt alloys a-286 rene 41® and others special dry film lubricants or silverplating in the race i.d are sometimes used in these bearings 10 two-piece swage-coined rod ends page 56 11 should be used primarily for applications which require high load carrying capac
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engineering fahrenheit/celsius conversion table the numbers in center column refer to the temperatures either in celsius or fahrenheit which need conversion to the other scale when converting from fahrenheit to celsius the equivalent temperature will be found to the left of the center column if converting from celsius to fahrenheit the answer will be found to the right table 13 fahrenheit/celsius conversion table °c °c/°f °f °c °c/°f °f °c °c/°f °f -79 -73 -68 -62 -57 -51 -45 -40 -34 -29 -23 -17.7 -17.2 -16.6 -16.1 -15.5 -15.0 -14.4 -13.9 -13.3 -12.7 -12.2 -6.6 -1.1 4.4 9.9 15.6 21.0 26.8 32.1 37.7 43 49 54 60 65 71 76 83 88 -110 -100 -90 -80 -70 -60 -50 -40 -30 -20 -10 0 1 2 3 4 5 6 7 8 9 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 -166 -148 -130 -112 -94 -76 -58 -40 -22 -4 14 32 33.8 35.6 37.4 39.2 41.0 42.8 44.6 46.4 48.2 50.0 68.0 86.0 104.0 122.0 140.0 158.0 176.0 194.0 212 230 248 266 284 302 320 338 356 374 93 99 104 110 115 121 127 132 138 143 149 154 160
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capabilities ongoing new product development hitech division ultra precision machine tool bearings precision division miniature and instrument our facilities include · cad cam-based manufacturing and design · metallurgy and testing laboratories · class 10,000 clean room · class 100 clean workstations · world class manufacturing · comprehensive life testing astro division composite components 92
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