ASME B18.31.3 Threaded Rods

ASME B18.31.3 Standard covers the general and dimensional data for inch series threaded rods.
Included are the following thread configurations and diameters:

• UNC threads #4 through 4 in.
• UNF threads #4 through 1 1⁄2 in.
• 8UN threads 1 1⁄8 in. through 4 in.
• Acme threads 1⁄4 in. through 5 in.

At this time, there are no ISO standards for inch threaded rods. The inclusion of dimensional data in this Standard is not intended to imply that all of the products described herein are stock production sizes. Consumers should consult with suppliers concerning lists of stock production sizes.

ASME B18.31.3 Dimensions (mm)

Size	Nominal Diameter	Size and Threads/Inch
		UNC	8UN	UNF	Acme
#4	0.1120	4-40	...	4-48	...
#5	0.1250	5-40	...	5-44	...
#6	0.1380	6-32	...	6-40	...
#8	0.1640	8-32	...	8-36	...
#10	0.1900	10-24	...	10-32	...
#12	0.2160	12-24	...	12-28	...
1/4	0.2500	1/4-20	...	1/4-28	1/4-16
5/16	0.3125	5/16-18	...	5/16-24	5/16-14
3/8	0.3750	3/8-16	...	3/8-24	3/8-12
7/16	0.4370	7/16-14	...	7/16-20	7/16-12
1/2	0.5000	1/2-13	...	1/2-20	1/2-10
9/16	0.5620	9/16-12	...	9/16-18	...
5/8	0.6250	5/8-11	...	5/8-18	5/8-8
3/4	0.7500	3/4-10	...	3/4-16	3/4-6
7/8	0.8750	7/8-9	...	7/8-14	7/8-6
1	1.0000	1-8	...	1-12 or 1-14 UNS	1-5
1 1/8	1.1250	1 1/8-7	1 1/8-8	1 1/8-12	1 1/8-5
1 1/4	1.2500	1 1/4-7	1 1/4-8	1 1/4-12	1 1/4-5
1 3/8	1.3750	1 3/8-6	1 3/8-8	1 3/8-12	1 3/8-4
1 1/2	1.5000	1 1/2-6	1 1/2-8	1 1/2-12	1 1/2-4
1 5/8	1.6250	...	1 5/8-8	...	...
1 3/4	1.7500	1 3/4-5	1 3/4-8	...	1 3/4-4
1 7/8	1.8750	...	1 7/8-8	...	...
2	2.0000	2-4.5	2-8	...	2-4
2 1/4	2.2500	2 1/4-4.5	2 1/4-8	...	2 1/4-3
2 1/2	2.5000	2 1/2-4	2 1/2-8	...	2 1/2-3
2 3/4	2.7500	2 3/4-4	2 3/4-8	...	2 3/4-3
3	3.0000	3-4	3-8	...	3-2
3 1/4	3.2500	3 1/4-4	3 1/4-8	...	...
3 1/2	3.5000	3 1/2-4	3 1/2-8	...	3 1/2-2
3 3/4	3.7500	3 3/4-4	3 3/4-8	...	...
4	4.0000	4-4	4-8	...	4-2
4 1/2	4.5000	...	...	...	4 1/2-2
5	5.0000	...	...	...	5-2

ASME B18.31.3 Dimensions (Inch)

Size	Nominal Diameter	Size and Threads/Inch
		UNC	8UN	UNF	Acme
#4	2.845	4-40	...	4-48	...
#5	3.175	5-40	...	5-44	...
#6	3.505	6-32	...	6-40	...
#8	4.166	8-32	...	8-36	...
#10	4.826	10-24	...	10-32	...
#12	5.486	12-24	...	12-28	...
1/4	6.350	1/4-20	...	1/4-28	1/4-16
5/16	7.938	5/16-18	...	5/16-24	5/16-14
3/8	9.525	3/8-16	...	3/8-24	3/8-12
7/16	11.100	7/16-14	...	7/16-20	7/16-12
1/2	12.700	1/2-13	...	1/2-20	1/2-10
9/16	14.275	9/16-12	...	9/16-18	...
5/8	15.875	5/8-11	...	5/8-18	5/8-8
3/4	19.050	3/4-10	...	3/4-16	3/4-6
7/8	22.225	7/8-9	...	7/8-14	7/8-6
1	25.400	1-8	...	1-12 or 1-14 UNS	1-5
1 1/8	28.575	1 1/8-7	1 1/8-8	1 1/8-12	1 1/8-5
1 1/4	31.750	1 1/4-7	1 1/4-8	1 1/4-12	1 1/4-5
1 3/8	34.925	1 3/8-6	1 3/8-8	1 3/8-12	1 3/8-4
1 1/2	38.100	1 1/2-6	1 1/2-8	1 1/2-12	1 1/2-4
1 5/8	41.275	...	1 5/8-8	...	...
1 3/4	44.450	1 3/4-5	1 3/4-8	...	1 3/4-4
1 7/8	47.625	...	1 7/8-8	...	...
2	50.800	2-4.5	2-8	...	2-4
2 1/4	57.150	2 1/4-4.5	2 1/4-8	...	2 1/4-3
2 1/2	63.500	2 1/2-4	2 1/2-8	...	2 1/2-3
2 3/4	69.850	2 3/4-4	2 3/4-8	...	2 3/4-3
3	76.200	3-4	3-8	...	3-2
3 1/4	82.550	3 1/4-4	3 1/4-8	...	...
3 1/2	88.900	3 1/2-4	3 1/2-8	...	3 1/2-2
3 3/4	95.250	3 3/4-4	3 3/4-8	...	...
4	101.600	4-4	4-8	...	4-2
4 1/2	114.300	...	...	...	4 1/2-2
5	127.000	...	...	...	5-2