美制內(nèi)螺紋（2B）常用規(guī)格極限尺寸表（粗牙）
公稱尺寸和每英寸牙數(shù)
螺紋系列代號
小徑極限
中徑極限
大徑min
底孔直徑
最小
最大
8-32
UNC
0.1300
0.1390
0.1437
0.1475
0.1640
3.40
3.50
(0.164-32)
3.3020
3.5306
3.6500
3.7465
4.1656
10-24
0.1450
0.1560
0.1629
0.1672
0.1900
3.75
3.90
(0.190-24)
3.6830
3.9624
4.1377
4.2469
4.8260
12-24
0.1710
0.1810
0.1889
0.1933
0.2160
4.40
4.55
(0.216-24)
4.3434
4.5974
4.7981
4.9098
5.4864
1/4-20
0.1960
0.2070
0.2175
0.2224
0.2500
5.05
5.20
(0.250-20)
4.9784
5.2578
5.5245
5.6490
6.3500
5/16-18
0.2520
0.2650
0.2764
0.2817
0.3125
6.45
6.60
(0.3175-18)
6.4008
6.7310
7.0206
7.1552
7.9375
3/8-16
0.3070
0.3210
0.3344
0.3401
0.3750
7.85
8.00
(0.375-16)
7.7978
8.1534
8.4938
8.6385
9.5250
7/16-14
0.3600
0.3760
0.3911
0.3972
0.4375
9.20
9.40
(0.4375-14)
9.1440
9.5504
9.9339
10.0889
11.1125
1/2-13
0.4170
0.4340
0.4500
0.4565
0.5000
10.65
10.90
(0.50-13)
10.5918
11.0236
11.4300
11.5951
12.7000
9/16-12
0.4720
0.4900
0.5084
0.5152
0.5625
12.05
12.30
(0.5625-12)
11.9888
12.4460
12.9134
13.0861
14.2875
5/8-11
0.5270
0.5460
0.5660
0.5732
0.6250
13.45
13.70
(0.625-11)
13.3858
13.8684
14.3764
14.5593
15.8750
3/4-10
0.6420
0.6630
0.6850
0.6927
0.7500
16.40
16.70
(0.750-10)
16.3068
16.8402
17.3990
17.5946
19.0500
7/8-9
0.7550
0.7780
0.8028
0.8110
0.8750
19.30
19.60
(0.875-9)
19.1770
19.7612
20.3911
20.5994
22.2250
1"-8
0.8650
0.8900
0.9188
0.9276
1.0000
22.10
22.40
(1.000-8)
21.9710
22.6060
23.3375
23.5610
25.4000
1.底孔直徑指攻絲前鉆孔直徑，鑄鐵、黃銅等較軟料取小值，鋼、青銅等較硬料取大值。
2.標(biāo)記示例：10-24UNC-2B(或0.190-24UNC-2B)、3/8-16UNC-2B(或0.375-16UNC-2B)
