Machinery's Handbook, 31st Edition
994
Taps Table 13b. Straight and Taper Pipe Taps Tolerances (Ground and Cut Thread) ANSI/ASME B94.9-2008 (R2018) Ground Thread Cut Thread
Nominal Diameter Range, inch
Nominal Diameter Range, inch
Tolerances, inch
Tolerances, inch
To (inclusive)
To (inclusive)
Element
Element
Over
Over
±0.031 ±0.063 ±0.063 ±0.094 ±0.125
±0.031 ±0.063 ±0.063 ±0.094 ±0.125 ±0.031 ±0.063 - 0.007 - 0.009 - 0.004 - 0.006 - 0.008
1 ⁄ 16
3 ⁄ 4
1 ⁄ 8
3 ⁄ 4
Length overall, L
Length overall, L
1
2
1
3
1 ⁄ 16
3 ⁄ 4
1 ⁄ 8
3 ⁄ 4
Length of thread, I
Length of thread, I
1
1
1 1 ⁄ 4
1 1 ⁄ 4
2
3
1 1 ⁄ 2 1 ⁄ 16
1 1 ⁄ 2
±0.031 Length of square, I 2 - 0.002 Diameter of shank, d 1 ±0.063
3 ⁄ 4
1 ⁄ 8
3 ⁄ 4
Length of square, I 2
1
2
1
3
1 ⁄ 16
1 ⁄ 8
1 ⁄ 8
1 ⁄ 2
Diameter of shank, d 1
1 2
3
- 0.002 - 0.002 - 0.004 - 0.006 - 0.008
1 ⁄ 4
3 ⁄ 4
… 3 ⁄ 4
1 1 ⁄ 4 1 ⁄ 16
1 ⁄ 8
Size of square, a
1 ⁄ 8
1 ⁄ 4
Size of square, a
1
3
3 ⁄ 4
1 ⁄ 4
1
2
All dimensions are given in inches. The first few threads on interrupted thread pipe taps are left full. These taps have internal centers. For runout tolerances of tap elements, see Table 14. Taps marked NPS are suitable for NPSC and NPSM. These taps have 2 to 3 1 ⁄ 2 threads chamfer, see Table 5a. Optional neck is for manufacturing use only. For taper pipe thread limit, see Table 24a. For straight pipe thread limits, see Table 23a, Table 23b, and Table 23d. Table 14. Runout and Locational Tolerance of Tap Elements ANSI/ASME B94.9-2008 (R2018)
A-B
, a
,
d 1 , A-B
,
A
B
c , A-B Chamfer
,
, A-B Pitch Diameter d 2 ,
d a ,A-B Major Diameter ,
Range Sizes (Inclusive)
Total Runout FIM, Inch
Pipe, Inch Cut Thread
Ground Thread 0.0010 0.0016 0.0010 0.0016 0.0010 0.0016 0.0020 0.0030
Location, Inch
Machine Screw
Metric
M1.6 to M8 M10 to M100 M1.6 to M8 M10 to M100 M1.6 to M8 M10 to M100 M1.6 to M12 M14 to M100 M1.6 to M12 M14 to M100
0.0060 0.0080 0.0050 0.0080 0.0050 0.0080 0.0040 0.0060
… … … … … … … …
#0 to 5 ⁄ 16 11 ⁄ 32 to 4 #0 to 5 ⁄ 16 11 ⁄ 32 to 4 #0 to 5 ⁄ 16 11 ⁄ 32 to 4 #0 to 1 ⁄ 2 17 ⁄ 32 to 4 #0 to 1 ⁄ 2
1 ⁄ 16
Shank, d 1
1 ⁄ 8 to 4
1 ⁄ 16
Major diameter, d a
1 ⁄ 8 to 4
1 ⁄ 16
Pitch Diameter, d 2
1 ⁄ 8 to 4 1 ⁄ 16 to 1 ⁄ 8 1 ⁄ 8 to 4 1 ⁄ 16 to 1 ⁄ 8 1 ⁄ 8 to 4
Chamfer a , c
… …
… …
0.0060
Square, a
17 ⁄ 32 to 4 0.0080 a Chamfer should preferably be inspected by light projection to avoid errors due to indicator contact points dropping into the thread groove.
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