Machinery's Handbook, 31st Edition
2146
Thread Gages Table 4. American National Standard Tolerance for GO, HI, and LO Thread Gages for Unified Inch Screw Thread
Tolerance on Lead a
Tol. on Major and Minor Diams. b
Tolerance on Pitch Diameter b
Tol. on Thread Half- angle ( ± ), minutes
To & incl. 1 ∕ 2 in. Dia.
To & incl. 1 ∕ 2 in. Dia.
Above 1 ∕ 2 to 4 in. Dia.
To & incl. 1 ∕ 2 in. Dia.
Above 1 ∕ 2 to 1 1 ∕ 2 in. Dia.
Above 1 1 ∕ 2 to
Above 4 to
Above 8 to 12 in. c Dia.
Thds. per Inch
Above 1 ∕ 2 in. Dia.
Above 4 in. Dia.
4 in. Dia.
8 in. Dia.
W GAGES
80, 72 .0001 .00015 20
.0003 .0003 .0003 .0004 .0003 .0004 .0003 .0004 .0003 .0004 .0003 .0004
… .0001 .00015 … … … … .0001 .00015 … … …
64 56 48 36 32
.0001 .00015 20 .0001 .00015 20 .0001 .00015 18 .0001 .00015 12 .0001 .00015 12
… .0001 .00015 .0002 … .0001 .00015 .0002 … .0001 .00015 .0002 … .0001 .00015 .0002
… … … … … … … …
44, 40 .0001 .00015 15
.0003 .0005 .0007 .0001 .00015 .0002 .00025 .0003 .0005 .0005 .0007 .0001 .00015 .0002 .00025 .0003 .0005 .0005 .0007 .0001 .00015 .0002 .00025 .0003 .0005 .0005 .0007 .0001 .00015 .0002 .00025 .0003 .0006 .0006 .0009 .0001 .0002 .00025 .0003 .0004 .0006 .0006 .0009 .00015 .0002 .00025 .0003 .0004 .0006 .0006 .0009 .00015 .0002 .00025 .0003 .0004 .0006 .0006 .0009 .00015 .0002 .00025 .0003 .0004 .0006 .0006 .0009 .00015 .0002 .00025 .0003 .0004
28, 27 .00015 .00015 24, 20 .00015 .00015 18 .00015 .00015 16 .00015 .00015 14, 13 .0002 .0002
8 8 8 8 6 6 6 6 6 6 5 5 5 4 4 4
12
.0002 .0002 .0002 .0002 .0002 .0002 … .00025 … .00025 … .00025 … .0003 … .0003 … .0003 … .0003 … .0003
11 1 ∕ 2
11 10
… .0006 .0009 … .0007 .0011 … .0007 .0011 … .0007 .0011 … .0008 .0013 … .0008 .0013 … .0008 .0013 … .0009 .0015
… .0002 .0025 .0003 .0004 … .0002 .00025 .0003 .0004 … .0002 .00025 .0003 .0004 … .0002 .00025 .0003 .0004 … .0002 .00025 .0003 .0004 … … .00025 .0003 .0004 … … .00025 .0003 .0004 … … .00025 .0003 .0004
9 8 7 6 5
4 1 ∕ 2
4
X GAGES
80, 72 .0002 .0002 .0002 .0002 56, 48 .0002 .0002 44, 40 .0002 .0002 64 .0002 .0002 32, 28 .0003 .0003 27, 24 .0003 .0003 36 16, 14 .0003 .0003 13, 12 .0003 .0003 11, 10 .0003 .0003 .0003 .0003 8, 7 .0004 .0004 20 18 .0003 .0003 .0003 .0003 11 1 ∕ 2 .0003 .0003
30 30 30 20 20 15 15 15 10 10 10 10 10 10
.0003 .0003 .0004 .0004 .0004 .0004 .0004 .0004 .0004 .0004
… .0002 .0002 … .0002 .0002
… … … … … …
… .0002 .0002 .0003 … .0002 .0002 .0003 … .0002 .0002 .0003
… … … … … …
.0005 .0005 .0007 .0003 .0003 .0004 .0005 .0006 .0005 .0005 .0007 .0003 .0003 .0004 .0005 .0006 .0005 .0005 .0007 .0003 .0003 .0004 .0005 .0006 .0005 .0005 .0007 .0003 .0003 .0004 .0005 .0006 .0006 .0006 .0009 .0003 .0003 .0004 .0006 .0008 .0006 .0006 .0009 .0003 .0003 .0004 .0006 .0008 .0006 .0006 .0009 .0003 .0003 .0004 .0006 .0008 .0006 .0006 .0009 .0003 .0003 .0004 .0006 .0008 .0007 .0007 .0011 .0003 .0003 .0004 .0006 .0008 .0007 .0007 .0011 .0004 .0004 .0005 .0006 .0008 .0008 .0008 .0013 .0004 .0004 .0005 .0006 .0008
9 6
5 5 5 5
.0004 .0004 .0004 .0004 .0004 .0004
.0008 .0008 .0013 .0009 .0009 .0015
… … .0005 .0006 .0008
5, 4 1 ∕ 2
4 … … .0005 .0006 .0008 a Allowable variation in lead between any two threads not farther apart than the length of the standard gage as shown in ANSI/ASME B47.1. The tolerance on lead establishes the width of a zone, measured parallel to the axis of the thread, within which the actual helical path must lie for the specified length of the thread. Measurements are taken from a fixed reference point, located at the start of the first full thread, to a sufficient number of positions along the entire helix to detect all types of lead variations. The amounts that these positions vary from their basic (theoretical) positions are recorded with due respect to sign. The greatest variation in each direction (±) is selected, and the sum of their values, disregarding sign, must not exceed the tolerance limits specified for W gages. b Tolerances apply to designated size of thread. The application of the tolerances is specified in the Standard. c Above 12 in. the tolerance is directly proportional to the tolerance given in this column below, in the ratio of the diameter to 12 in. All dimensions are given in inches unless otherwise specified.
Copyright 2020, Industrial Press, Inc.
ebooks.industrialpress.com
Made with FlippingBook - Share PDF online