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Definition
| Dimension that is the theoreetical size from which the limits for that dimension are derived, by the application of the allowance and tolerance |
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| Total permissible variation in size. Different between limits in size. |
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Definition
| Maximum and minimum sizes permitted for a specific dimension |
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Definition
| Intentional difference in size of mating parts. |
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| Tolerance that is expressed as plus and minus values. EXAMPLE 0.500 +.006 - .003 |
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Definition
| Applies in one direction from the specified size, the permissable variation in the other direction is zero. |
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Definition
| Range of tightness or looseness resulting from allowances and tolerances. 3 types Clearance, Interference, Transition |
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Definition
| Clearance always results when parts are assembled. Intended for accurate assembly of parts and bearings. Can be assembled by hand. |
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Definition
| Interference always results. Hole size is smaller than shaft. Dowel pins, etc. Usually assembled using arbor press. |
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Definition
| Either clearance or interference can result. Compromise bewtween interference and clearance fits. |
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Definition
| Intended to provide suitable lubrication allowance. |
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Definition
| Intended to determine only the location of the mating parts. 3 Groups: Clearance Fits, Transition Fits, and Interence Fits |
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Term
| Locational Clearance Fits |
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Definition
| Intended for parts that are normally stationary but can be assembled/disassembled easily |
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Term
| Locational Transition Fits |
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Definition
| Compromise between clearance and interfence fits. Used when accuracy of location is important, but small amount of clearance or interference is ok |
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Term
| Locational Interference Fit |
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Definition
| Used where accuaracy of location is of prime importance and for parts requiring rigidity and alignment |
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Term
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Definition
| Special type of interference fit. Normally characterized by constant bore pressures throughout the range of sizes. Interference varies with diameter, small difference bewteen max/min |
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Definition
Used for design sketches.
RC - Running and sliding fit
LC - Locational clearance fit
LT - Locational Transition fit
LN - Locational Interference fit
FN - Force or shrink fit |
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Term
| RC1 Precision Sliding Fit |
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Definition
| Intended for accurate location of parts to assemble without perceptible play for high precision work such as gauges |
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Term
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Definition
| Intended for the accurate location, but with greater maximum clearance that RC1. Parts move and turn easily but are not intended to run freely |
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Definition
| Intended for the accurate location, but with greater maximum clearance that RC1. Parts move and turn easily but are not intended to run freely |
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Term
| RC3 Precision Running Fit |
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Definition
| Closest fit that can be expected to run freely, intended for precision work, oil lubricated bearings at slow speeds and light journal pressures |
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Term
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Definition
| Intended chiefly as a running fit for grease or oil bearingson accurate machinery with moderate surface speeds and journal pressures, where accuarate location and minumum play are desired. |
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Term
| RC5 and RC6 Medium Running Fits |
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Definition
| Intended for higher running speeds and/or temperature variations. |
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Term
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Definition
| Accuracy is not essential, and/or large temperature variations are likely |
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Term
| RC8 and RC9 Loose Running Fits |
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Definition
| Used where materials made to commercial tolerances are involved, cold-rolled shafting, tubing, etc |
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Term
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Definition
| Minumum zero clearance, but in practice,probablity is that the fit will always have a clerance |
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Term
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Definition
| Small minumum clearance intended for close location fits for non-running parts |
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Definition
| Progressively larger clearances and tolerances. Loose clearances for bolts, and similar parts. |
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Definition
| Slight clearance, light push fit |
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Term
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Definition
| Virtually no clearance, for use where some interference can be tolerated. Referred to as easy keying fit, used for shaft keys, ball race fits. Assembly by hammer or pressure |
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Term
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Definition
| Slight interference, appreciable force will be required |
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Term
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Definition
| Light Press Fits, small minimum interference. Dowel pins assembled in arbor press in steel, cast iron, or brass. Can be dismantled and reassembled |
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Term
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Definition
| Heavy press fit in steel and brass. Light press fit in elastic material or light alloys |
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Term
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Definition
| Light Press Fits, small minimum interference. Dowel pins assembled in arbor press in steel, cast iron, or brass. Can be dismantled and reassembled |
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Term
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Definition
| LN4 can be used for permanent assembly of steel parts. These fits are primarily intended as press fits for soft materials |
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Term
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Definition
| Light assembly pressure and produces more or less permanent assemblies. Thin sections or long fits, cast-iron external members |
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Definition
| Heavier steel parts, or shrink fit on light sections |
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Definition
| Suitable for heavier steel parts, or shrink fit in medium sections |
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Definition
| Suitable for parts than can be highly stressed |
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Definition
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Definition
| Expressed in mincroinches, micrometers, or roughness grade numbers (N1-N12) |
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Definition
| Direction of the predominant surface pattern, ordinarily determined by the production method used |
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Definition
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Term
| Two Principle reasons for surface finish control |
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Definition
1) Friction Reduction
2) Control of Wear |
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Term
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Definition
| Ratio of the difference in diameters of two sections along a conical-shape part (perpendicular to the axis) |
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Term
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Definition
| Machining of a surface to create uniform depressions |
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Term
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Definition
| Cutting of a recess in a cylinder. Listed by width first and then diameter. If radius is present, assumed to be half the width unless specified. |
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Definition
| Slope - used as locking devices..taper keys, adjusting shims |
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Term
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Definition
| Cutting away inside or outside corner to facilitate assembly Never measured along angular surface |
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Definition
| Conical depression cut to recieve a countersunk type of screw or rivet |
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Definition
| Machined larger to a given depth to recieve a bolt, filister, hex head |
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Definition
| Area is machined just enough to provide level seating for bolt head, nut or washer. Specified by diameter of the hole first, then diameter of spotface. No depth is given |
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Definition
| Indicates where imaginary cutting takes place in secitonal view |
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Definition
| Identifies surface that has been cut, makes it stand out clearly |
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Definition
| Used to shorten view of long uniform sections |
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Definition
| Indicated by underlined dimension . Old methods were NTS and wavy lines |
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Definition
| Process of using a drill to cut a hole through a solid, or to enlarge an existing hole |
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Term
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Definition
| Process of sizing a hole to a given diameter with a reamer to produce a hole that is round, smooth,straight and accurate |
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Term
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Definition
| Enlargement of a hole by boring tool. |
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Definition
| Additional metal allowed in the inner intersection of two surfaces to increase the strength |
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Definition
| Denotes point or surface between which a dimension applies |
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Definition
| Used to direct dimensions or notes to the surface or points to which they apply |
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Term
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Definition
| European and Asian countries use First Angle |
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Term
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Definition
| US and Canada use Third Angle |
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Term
| Front view of 3rd Angle Projection |
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Definition
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Term
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Definition
Drawing that supplies information and instructions for manufacture or construction of machines or structures.
2 groups - Detail Drawings , Assembly |
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Term
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Definition
| Type of working drawing that provides necessary information for the manufacture of the parts for a specific product or structure. |
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Definition
| Working drawing that supplies information necessary for assembly of parts |
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Term
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Definition
| Object lines that define exterior shape of an object |
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