美制螺纹标准

美制粗螺纹				美制细螺纹
规格 （UNC)	标准径	2级牙钻孔径		规格 （UNF)	标准径	2级牙钻孔径
		最大	最小			最大	最小
NO.1-64(1.854)	1.55	1.582	1.425	NO.0-80(1.524)	1.25	1.305	1.182
NO.2-56(2.184)	1.80	1.871	1.695	NO.1-72(1.854)	1.55	1.612	1.474
NO.3-48(2.515)	2.10	2.146	1.941	NO.2-64(2.184)	1.85	1.912	1.756
NO.4-40(2.845)	2.30	2.385	2.157	NO.3-56(2.515)	2.10	2.197	2.025
NO.5-40(3.175)	2.60	2.697	2.487	NO.4-48(2.845)	2.40	2.458	2.271
NO.6-32(3.505)	2.80	2.895	2.642	NO.5-44(3.175)	2.70	2.740	2.551
NO.8-32(4.166)	3.40	3.530	3.302	NO.6-40(3.505)	2.90	3.022	2.820
NO.10-24(4.826)	3.90	3.962	3.683	NO.8-36(4.166)	3.50	3.606	3.404
NO.12-24(5.486)	4.50	4.597	4.344	NO.10-32(4.826)	4.10	4.165	3.963
1/4 -20	5.10	5.257	4.979	NO.12-28(5.846)	4.60	4.724	4.496
5/16 -18	6.60	6.731	6.401	1/4-28	5.50	5.588	5.360
3/8 -16	8.00	8.153	7.798	5/16-24	6.90	7.035	6.782
7/16 -14	9.40	9.550	9.144	3/8-24	8.50	8.636	8.382
1/2 -13	10.80	11.023	10.592	7/16-20	9.90	10.033	9.729
9/16 -12	12.20	12.446	11.989	1/2-20	11.50	11.607	11.329
5/8 -11	13.60	12.868	13.386	9/16-18	12.90	13.081	12.751
3/4 -10	16.50	18.840	16.307	5/8-18	14.50	14.681	14.351
7/8 -9	19.50	19.761	19.177	3/4-16	17.50	17.678	17.323
1-8	22.20	22.606	21.971	7/8-14	20.50	20.675	20.270
1-1/8-7	25.00	25.349	24.638	1-12	23.20	23.571	23.114
1-1/4-7	28.20	28.524	27.813	1-1/8-12	26.50	26.746	26.289
1-3/8-6	30.80	31.115	30.353	1-1/4-12	29.50	29.921	29.464
1-1/2-6	34.00	34.290	33.528	1-3/8-12	32.80	33.096	32.639
1-3/4-5	39.50	39.827	38.964	1-1/2-12	36.0	36.271	35.814
2-4-1/2	45.20	45.593	44.679
美制迫牙丝攻钻孔径				美制特细螺纹
规格	精度等级			规格 （UNEF)	标准径	2级牙钻孔径
	G4-G6	G7-G8	G9			最大	最小
NO.2-56UNC	1.94	-	-	NO.12-32	4.70	4.826	4.623
NO.3-48	2.23	-	-	1/4--32	5.60	5.690	5.486
NO.4-40	2.50	-	-	5/16-32	7.10	7.264	7.087
NO.5-40	2.83	-	-	3/8-32	8.70	8.865	8.661
NO.6-32	3.07	-	-	7/16-28	10.20	10.338	10.135
NO.8-32	3.73	3.77	-	1/2-28	11.80	11.938	11.709
NO.10-24	4.24	4.30	-	9/16-24	13.20	13.386	13.132
NO.12-24	4.90	4.96	-	5/8-24	14.80	14.986	14.732
1/4-20	-	5.72	-	3/4-20	17.80	17.958	17.678
5/16-18	-	7.24	-	7/8-20	21.00	21.133	20.853
3/8-16	-	8.74	8.81	1-20	24.00	24.308	24.028
7/16-14	-	10.20	10.30	美制管螺纹
1/2-13		11.27	11.82
NO.2-64UNF	1.97	-	-	规格	钻孔径
NO.3-56	2.27	-	-		NPT		NPS
NO.4-48	2.56	-	-		使用绞刀时	不用绞刀时
NO.5-44	2.86	-	-	1/16-27	6.10	6.25	6.35
NO.6-40	3.16	-	-	1/8-27	8.33	8.43	8.74
NO.8-36	3.78	-	-	1/4-18	10.72	11.13	11.13
NO.10-32	4.39	4.43	-	3/8-18	14.27	14.27	14.68
NO.12-28	4.99	5.04	-	1/2-14	17.48	17.86	18.26
1/4-28	5.85	5.90	-	3/4-14	22.63	23.01	23.42
5/16-24	7.36	7.41	-	1-11-1/2	28.58	28.98	29.36
3/8-24	-	9.00	-	1-1/4-11-1/2	37.31	37.69	38.10
7/16-20	-	10.48	10.54	1-1/2-11-1/2	43.66	44.04	44.45
1/2-20	-	12.07	12.13	2-11-1/2	55.58	55.96	56.36
				英制电器螺纹
				规格	钻孔径
				2BA	4.0-4.2
				3BA
				4BA	3.0-3.2
				5BA	2.7-2.8