UNEF – Unified Extra Fine 60° (mm)

British Standard Whitworth Coarse Thread Series (parallel, cylindrical) In GB most common Thread. Corresponds to the Metric Thread in its type of use.

UNEF – 8 Threads Per Inch
Nominal Dia.	TPI	Pitch	Tap Size
1-1/16”	8	3.175	24.00
1-1/8”	8	3.175	25.50
1-3/16”	8	3.175	27.20
1-1/4”	8	3.175	28.80
1-5/16”	8	3.175	30.30
1-3/8”	8	3.175	31.90
1-7/16”	8	3.175	33.50
1-1/2”	8	3.175	35.10
1-9/16”	8	3.175	36.70
1-5/8”	8	3.175	38.30
1-11/16”	8	3.175	39.90
1-3/4”	8	3.175	41.40
1-13/16”	8	3.175	43.00
1-7/8”	8	3.175	44.60
1-15/16”	8	3.175	46.20
2”	8	3.175	47.80
2-1/8”	8	3.175	51.00
2-1/4”	8	3.175	54.10
2-3/8”	8	3.175	57.30
2-1/2”	8	3.175	60.50
2-5/8”	8	3.175	64.70
2-3/4”	8	3.175	66.80
2-7/8”	8	3.175	70.00
3”	8	3.175	73.20
3-1/8”	8	3.175	76.40
3-1/4”	8	3.175	79.50
3-3/8”	8	3.175	82.70
3-1/2”	8	3.175	85.90
3-5/8”	8	3.175	89.00
3-3/4”	8	3.175	92.30
3-7/8”	8	3.175	95.40
4”	8	3.175	98.60
UNEF – 12 Threads Per Inch
Nominal Dia.	TPI	Pitch	Tap Size
5/8”	12	2.117	13.90
11/16”	12	2.117	15.50
3/4”	12	2.117	17.00
13/16”	12	2.117	18.60
7/8”	12	2.117	20.20
15/16”	12	2.117	21.80
1-1/16”	12	2.117	25.00
1-3/16”	12	2.117	28.20
1-5/16”	12	2.117	31.30
1-7/16”	12	2.117	34.50
1-9/16”	12	2.117	37.70
1-5/8”	12	2.117	39.30
1-11/16”	12	2.117	40.85
1-3/4”	12	2.117	42.40
1-13/16”	12	2.117	44.00
1-7/8”	12	2.117	45.60
1-15/16”	12	2.117	47.20
2”	12	2.117	48.80
2-1/8”	12	2.117	52.00
2-1/4”	12	2.117	55.10
2-3/8”	12	2.117	58.30
2-1/2”	12	2.117	61.50
2-5/8”	12	2.117	64.70
2-3/4”	12	2.117	67.80
2-7/8”	12	2.117	71.00
3”	12	2.117	74.20
3-1/8”	12	2.117	77.40
3-1/4”	12	2.117	80.50
3-3/8”	12	2.117	83.70
3-1/2”	12	2.117	86.90
3-5/8”	12	2.117	90.10
3-3/4”	12	2.117	93.25
3-7/8”	12	2.117	96.40
4”	12	2.117	99.60
4-1/8”	12	2.117	102.80
4-1/4”	12	2.117	105.90
4-3/8”	12	2.117	109.10
4-1/2”	12	2.117	112.30
4-5/8”	12	2.117	115.50
4-3/4”	12	2.117	118.70
4-7/8”	12	2.117	121.70
5”	12	2.117	125.00
5-1/8”	12	2.117	128.20
5-1/4”	12	2.117	131.40
5-3/8”	12	2.117	134.50
5-1/2”	12	2.117	137.70
5-5/8”	12	2.117	140.90
5-3/4”	12	2.117	144.00
6”	12	2.117	150.40
UNEF – 16 Threads Per Inch
Nominal Dia.	TPI	Pitch	Tap Size
7/16”	16	1.587	9.58
1/2”	16	1.587	11.20
9/16”	16	1.587	12.80
5/8”	16	1.587	14.40
11/16”	16	1.587	16.00
13/16”	16	1.587	19.10
7/8”	16	1.587	20.70
15/16”	16	1.587	22.30
1”	16	1.587	23.90
1-1/16”	16	1.587	25.50
1-1/8”	16	1.587	27.10
1-3/16”	16	1.587	28.70
1-1/4”	16	1.587	30.30
1-5/16”	16	1.587	31.75
1-3/8”	16	1.587	33.40
1-7/16”	16	1.587	35.00
1-1/2”	16	1.587	36.60
1-9/16”	16	1.587	38.20
1-5/8”	16	1.587	39.80
1-11/16”	16	1.587	41.35
1-3/4”	16	1.587	43.00
1-13/16”	16	1.587	44.50
1-7/8”	16	1.587	46.10
1-15/16”	16	1.587	47.70
2”	16	1.587	49.30
2-1/8”	16	1.587	52.60
2-1/4”	16	1.587	55.65
2-3/8”	16	1.587	58.85
2-1/2”	16	1.587	62.00
2-5/8”	16	1.587	65.15
2-3/4”	16	1.587	68.35
2-7/8”	16	1.587	71.50
3”	16	1.587	74.70
3-1/8”	16	1.587	77.85
3-1/4”	16	1.587	81.00
3-3/8”	16	1.587	84.20
3-1/2”	16	1.587	87.40
3-5/8”	16	1.587	90.55
3-3/4”	16	1.587	93.75
3-7/8”	16	1.587	96.90
4”	16	1.587	100.10
4-1/8”	16	1.587	103.30
4-1/4”	16	1.587	106.45
4-3/8”	16	1.587	109.60
4-1/2”	16	1.587	112.80
4-5/8”	16	1.587	116.00
4-3/4”	16	1.587	119.15
4-7/8”	16	1.587	122.30
5”	16	1.587	125.50
5-1/4”	16	1.587	131.85
5-1/2”	16	1.587	138.20
5-5/8”	16	1.587	141.35
5-7/8”	16	1.587	147.75
6”	16	1.587	150.90
UNEF – 18 Threads Per Inch
Nominal Dia.	TPI	Pitch	Tap Size
1-1/16”	18	1.411	25.80
1-1/8”	18	1.411	27.35
1-1/4”	18	1.411	30.55
1-5/16”	18	1.411	32.10
1-3/8”	18	1.411	33.70
1-7/16”	18	1.411	35.30
1-1/2”	18	1.411	36.90
1-9/16”	18	1.411	38.55
1-5/8”	18	1.411	40.10
1-11/16”	18	1.411	41.60
UNEF – 20 Threads Per Inch
Nominal Dia.	TPI	Pitch	Tap Size
5/16”	20	1.27	6.70
3/8”	20	1.27	8.30
9/16”	20	1.27	13.10
5/8”	20	1.27	14.67
11/16”	20	1.27	16.25
1-1/16”	20	1.27	25.80
1-1/8”	20	1.27	27.37
1-3/16”	20	1.27	28.97
1-1/4”	20	1.27	30.55
1-5/16”	20	1.27	32.15
1-3/8”	20	1.27	33.70
1-7/16”	20	1.27	35.32
1-1/2”	20	1.27	36.89
1-9/16”	20	1.27	38.49
1-5/8”	20	1.27	40.08
1-11/16”	20	1.27	41.68
1-3/4”	20	1.27	43.25
1-13/16”	20	1.27	44.84
1-7/8”	20	1.27	46.42
1-15/16”	20	1.27	48.00
2”	20	1.27	49.58
2-1/8”	20	1.27	52.78
2-1/4”	20	1.27	56.03
2-3/8”	20	1.27	59.12
2-1/2”	20	1.27	62.30
2-5/8”	20	1.27	65.47
2-3/4”	20	1.27	68.67
2-7/8”	20	1.27	71.82
3”	20	1.27	75.00
3/4”	20	1.27	18.00
13/16”	20	1.27	19.60
7/8”	20	1.27	21.15
15/16”	20	1.27	22.70
1”	20	1.27	24.30
UNEF – 24 Threads Per Inch
Nominal Dia.	TPI	Pitch	Tap Size
9/16”	24	1.058	13.40
5/8”	24	1.058	15.00
11/16”	24	1.058	16.60
UNEF – 28Threads Per Inch
Nominal Dia.	TPI	Pitch	Tap Size
7/16”	28	0.907	10.35
1/2”	28	0.907	11.80
UNEF – 32 Threads Per Inch
Nominal Dia.	TPI	Pitch	Tap Size
N 12	32	0.794	4.80
1/4”	32	0.794	5.70
5/16”	32	0.794	7.25
3/8”	32	0.794	8.85