Threads and Threading - Sportpilot.info

More documents

Recommendations

Info

Machinery's Handbook 27th Edition 1728 SCREW THREADS by hand, such as hose couplings and thread plug gages, to prevent cutting of hands and crossing of threads. It was formerly known as a Higbee cut. Chamfer: This is a conical surface at the starting end of a thread. Class of Thread: The class of a thread is an alphanumerical designation to indicate the standard grade of tolerance and allowance specified for a thread. Clearance Fit: This is a fit having limits of size so prescribed that a clearance always results when mating parts are assembled at their maximum material condition. Complete Thread: The complete thread is that thread whose profile lies within the size limits. (See also Effective Thread and Length of Complete Thread.) Note: Formerly in pipe thread terminology this was referred to as “the perfect thread” but that term is no longer considered desirable. Crest: This is that surface of a thread which joins the flanks of the thread and is farthest from the cylinder or cone from which the thread projects. Crest Truncation: This is the radial distance between the sharp crest (crest apex) and the cylinder or cone that would bound the crest. Depth of Thread Engagement: The depth (or height) of thread engagement between two coaxially assembled mating threads is the radial distance by which their thread forms overlap each other. Design Size: This is the basic size with allowance applied, from which the limits of size are derived by the application of a tolerance. If there is no allowance, the design size is the same as the basic size. Deviation: Deviation is a variation from an established dimension, position, standard, or value. In ISO usage, it is the algebraic difference between a size (actual, maximum, or minimum) and the corresponding basic size. The term deviation does not necessarily indicate an error. (See also Error.) Deviation, Fundamental (ISO term): For standard threads, the fundamental deviation is the upper or lower deviation closer to the basic size. It is the upper deviation es for an external thread and the lower deviation EI for an internal thread. (See also Allowance and Tolerance Position.) Deviation, Lower (ISO term): The algebraic difference between the minimum limit of size and the basic size. It is designated EI for internal and ei for external thread diameters. Deviation, Upper (ISO term): The algebraic difference between the maximum limit of size and the basic size. It is designated ES for internal and es for external thread diameters. Dimension: A numerical value expressed in appropriate units of measure and indicated on drawings along with lines, symbols, and notes to define the geometrical characteristic of an object. Effective Size: See Pitch Diameter, Functional Diameter. Effective Thread: The effective (or useful) thread includes the complete thread, and those portions of the incomplete thread which are fully formed at the root but not at the crest (in taper pipe threads it includes the so-called black crest threads); thus excluding the vanish thread. Error: The algebraic difference between an observed or measured value beyond tolerance limits, and the specified value. External Thread: A thread on a cylindrical or conical external surface. Fit: Fit is the relationship resulting from the designed difference, before assembly, between the sizes of two mating parts which are to be assembled. Flank: The flank of a thread is either surface connecting the crest with the root. The flank surface intersection with an axial plane is theoretically a straight line. Flank Angle: The flank angles are the angles between the individual flanks and the perpendicular to the axis of the thread, measured in an axial plane. A flank angle of a symmetrical thread is commonly termed the half-angle of thread. Flank Diametral Displacement: In a boundary profile defined system, flank diametral displacement is twice the radial distance between the straight thread flank segments of the Copyright 2004, Industrial Press, Inc., New York, NY
Machinery's Handbook 27th Edition SCREW THREADS 1729 maximum and minimum boundary profiles. The value of flank diametral displacement is equal to pitch diameter tolerance in a pitch line reference thread system. Height of Thread: The height (or depth) of thread is the distance, measured radially, between the major and minor cylinders or cones, respectively. Helix Angle: On a straight thread, the helix angle is the angle made by the helix of the thread and its relation to the thread axis. On a taper thread, the helix angle at a given axial position is the angle made by the conical spiral of the thread with the axis of the thread. The helix angle is the complement of the lead angle. (See also page 1966 for diagram.) Higbee Cut: See Blunt Start Thread. Imperfect Thread: See Incomplete Thread. Included Angle: This is the angle between the flanks of the thread measured in an axial plane. Incomplete Thread: A threaded profile having either crests or roots or both, not fully formed, resulting from their intersection with the cylindrical or end surface of the work or the vanish cone. It may occur at either end of the thread. Interference Fit: A fit having limits of size so prescribed that an interference always results when mating parts are assembled. Internal Thread: A thread on a cylindrical or conical internal surface. Lead: Lead is the axial distance between two consecutive points of intersection of a helix by a line parallel to the axis of the cylinder on which it lies, i.e., the axial movement of a threaded part rotated one turn in its mating thread. Lead Angle: On a straight thread, the lead angle is the angle made by the helix of the thread at the pitch line with a plane perpendicular to the axis. On a taper thread, the lead angle at a given axial position is the angle made by the conical spiral of the thread with the perpendicular to the axis at the pitch line. Lead Thread: That portion of the incomplete thread that is fully formed at the root but not fully formed at the crest that occurs at the entering end of either an external or internal thread. Left-hand Thread: A thread is a left-hand thread if, when viewed axially, it winds in a counterclockwise and receding direction. Left-hand threads are designated LH. Length of Complete Thread: The axial length of a thread section having full form at both crest and root but also including a maximum of two pitches at the start of the thread which may have a chamfer or incomplete crests. Length of Thread Engagement: The length of thread engagement of two mating threads is the axial distance over which the two threads, each having full form at both crest and root, are designed to contact. (See also Length of Complete Thread.) Limits of Size: The applicable maximum and minimum sizes. Major Clearance: The radial distance between the root of the internal thread and the crest of the external thread of the coaxially assembled designed forms of mating threads. Major Cone: The imaginary cone that would bound the crests of an external taper thread or the roots of an internal taper thread. Major Cylinder: The imaginary cylinder that would bound the crests of an external straight thread or the roots of an internal straight thread. Major Diameter: On a straight thread the major diameter is that of the major cylinder. On a taper thread the major diameter at a given position on the thread axis is that of the major cone at that position. (See also Major Cylinder and Major Cone.) Maximum Material Condition: (MMC): The condition where a feature of size contains the maximum amount of material within the stated limits of size. For example, minimum internal thread size or maximum external thread size. Minimum Material Condition: (Least Material Condition (LMC)): The condition where a feature of size contains the least amount of material within the stated limits of size. For example, maximum internal thread size or minimum external thread size. Minor Clearance: The radial distance between the crest of the internal thread and the root of the external thread of the coaxially assembled design forms of mating threads. Copyright 2004, Industrial Press, Inc., New York, NY
Page 1 and 2: SCREW THREAD SYSTEMS 1725 Screw Thr
Page 3 and 4: Machinery's Handbook 27th Edition O
Page 5 and 6: Machinery's Handbook 27th Edition T
Page 7: SCREW THREADS 1727 ISO Metric Threa
Page 11 and 12: Machinery's Handbook 27th Edition S
Page 13 and 14: UNIFIED SCREW THREADS 1733 UN Inter
Page 15 and 16: Machinery's Handbook 27th Edition U
Page 17 and 18: Nominal Size, Threads per Inch, and
Page 45 and 46: UNIFIED SCREW THREADS 1765 Table 4c
Page 49 and 50: UNIFIED SCREW THREADS 1769 Table 5d
Page 51 and 52: UNIFIED SCREW THREADS 1771 Table 5e
Page 57 and 58: Machinery's Handbook 27th Edition M
Page 59 and 60:
MINIATURE SCREW THREADS 1779 Table
Page 61 and 62:
;; ;;;; ;;;;;; ;;;;;;;; ;;;;;;;;;;
Page 63 and 64:
Machinery's Handbook 27th Edition M
Page 65 and 66:
Page 67 and 68:
METRIC SCREW THREADS M PROFILE 1787
Page 69 and 70:
Page 71 and 72:
Page 73 and 74:
Page 75 and 76:
Pitch P METRIC SCREW THREADS M PROF
Page 77 and 78:
Page 79 and 80:
Page 81 and 82:
Basic Thread METRIC SCREW THREADS M
Page 83 and 84:
Page 85 and 86:
METRIC SCREW THREADS MJ PROFILE 180
Page 87 and 88:
TRAPEZOIDAL METRIC THREADS 1807 Tol
Page 89 and 90:
TRAPEZOIDAL METRIC THREADS 1809 Tab
Page 91 and 92:
120 140 160 180 110 130 150 170 Mac
Page 93 and 94:
Machinery's Handbook 27th Edition T
Page 95 and 96:
Pitch P BRITISH STANDARD ISO METRIC
Page 97 and 98:
BRITISH STANDARD ISO METRIC SCREW T
Page 99 and 100:
BRITISH STANDARD ISO METRIC SCREW T
Page 101 and 102:
Nominal Diametera BRITISH STANDARD
Page 103 and 104:
Nominal Diameter BRITISH STANDARD I
Page 105 and 106:
Machinery's Handbook 27th Edition A
Page 107 and 108:
Page 109 and 110:
Table 2b. Limiting Dimensions of AN
Page 111 and 112:
Page 113 and 114:
CENTRALIZING ACME SCREW THREADS 183
Page 115 and 116:
Page 117 and 118:
Machinery's Handbook 27th Edition C
Page 119 and 120:
Table 8c. Limiting Dimensions of Am
Page 121 and 122:
Page 123 and 124:
Machinery's Handbook 27th Edition S
Page 125 and 126:
Table 14b. Limiting Dimensions for
Page 127 and 128:
Nominal Sizes Table 15. Stub Acme S
Page 129 and 130:
Machinery's Handbook 27th Edition B
Page 131 and 132:
Thds. a per Inch ANSI BUTTRESS THRE
Page 133 and 134:
ANSI BUTTRESS THREADS 1853 Table 3.
Page 135 and 136:
ANSI BUTTRESS THREADS 1855 The majo
Page 137 and 138:
Machinery's Handbook 27th Edition W
Page 139 and 140:
WHITWORTH THREADS 1859 Table 3. Bri
Page 141 and 142:
AMERICAN PIPE THREADS 1861 Table 1a
Page 143 and 144:
AMERICAN PIPE THREADS 1863 guide fo
Page 145 and 146:
Page 147 and 148:
DRYSEAL PIPE THREADS 1867 b PTF-SAE
Page 149 and 150:
Machinery's Handbook 27th Edition B
Page 151 and 152:
BRITISH PIPE THREADS 1871 British S
Page 153 and 154:
Page 155 and 156:
HOSE COUPLING SCREW THREADS 1875 Th
show all

Threads and Threading - Sportpilot.info

Create successful ePaper yourself

Delete template?

Save as template?