UNF Thread

The UNF thread is the "American fine thread" and is used in the USA, comparable to the metric fine thread in Europe. The fine thread achieves a higher holding force. In the UNF thread table below you will find technical data as well as tightening torque for UNF threads.

Example:

1/4 inch - 28 x 1/2 inch hex bolt

1/4 = Thread outer diameter 6.35 mm

28 = number of threads to inch (25.4 mm) length

1/2 = length of screw from head 12,70 mm

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UNF Thread Chart

UNF (Fine Thread) Flank Angle 60°
Technical Data:			Tightening Torque in (Nm)
Inch	Gear number per Inch (Zoll)	Thread Ø outside in mm	Grade 1 (equivalent to 4.6)	Grade 2 (equivalent to 5.6)	Grade 5 (equivalent to 8.8)	Grade 8 (equivalent to 10.9)
Nr. 000 (UNF 000-120)	120	0,864 mm
Nr. 00 (UNF 00-96)	96	1,194 mm
Nr. 0 (UNF 0-80)	80	1,524 mm
Nr. 1 (UNF 1-72)	72	1,854 mm
Nr. 2 (UNF 2-64)	64	2,184 mm
Nr. 3 (UNF 3-56)	56	2,515 mm
Nr. 4 (UNF 4-48)	48	2,845 mm
Nr. 5 (UNF 5-44)	44	3,175 mm
Nr. 6 (UNF 6-40)	40	3,505 mm
Nr. 8 (UNF 8-36)	36	4,166 mm
Nr. 10 (UNF 10-32)	32	4,763 mm
Nr. 12 (UNF 12-28)	28	5,486 mm
1/64"		0,397 mm
1/32"		0,794 mm
1/16"		1,587 mm
1/8"		3,175 mm
1/4"	28	6,350 mm	4	7	11	16
5/16"	24	7,938 mm	9	14	23	33
3/8"	24	9,525 mm	16	26	41	58
7/16"	20	11,112 mm	26	41	65	92
1/2"	20	12,700 mm	39	62	100	141
9/16"	18	14,288 mm	56	88	142	201
5/8"	18	15,875 mm	79	123	199	282
11/16"		17,462 mm
3/4"	16	19,050 mm	137	216	348	494
13/16"		20,638 mm
7/8"	14	22,225 mm	217	290	556	786
15/16"		23,812 mm
1"	12	25,400 mm	332	442	848	1199
1 1/8"	12	28,575 mm	471	626	1201	1696
1 1/4"	12	31,750 mm	655	873	1673	2365
1 3/8"	12	34,925 mm	883	1177	2255	3187
1 1/2"	12	38,100 mm	1158	1543	2959	4181
1 9/16"		39,688 mm
1 5/8"		41,275 mm	1485	1980	3794	5362
1 3/4"		44,450 mm	1869	2491	4776	6747
2"		50,800 mm	2823	3764	7215	10194
2 1/4"		57,150 mm	4057	5410	10369	14653
2 1/2"		63,500 mm	5608	7477	14332	20251

* All information without guarantee.

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