Taps / drill sizes
"G: Series
British Standard Pipe - Parallel ( Straight ) BSP or BSPF
Also referred to as British Gas,
British Pipe Parallel or Parallel Fastening thread.
Various Symbols: BSP, BSPP, BSSPI,
BSPF, BSPG, PS, R, G.
Taps Marked " G
Size I.S.O."
"Rc: Series
British Standard Pipe - Taper- BSPT
Also referred to as British Standard
Taper Pipe or Pipe Taper, or Conical Thread.
Taper is 3/4" taper per foot ( 1
in 16 on the diameter)
Various Symbols: BSPT, BSPTr, PT, KR,
Rc.
Taps Marked " Rc
Size I.S.O."
Nominal Size
(inches) |
T P I
|
Major Diameter
(inches) |
1/8"
|
28
|
0.383
|
1/4"
|
19
|
0.518
|
3/8"
|
19
|
0.656
|
1/2"
|
14
|
0.825
|
5/8"
|
14
|
0.902
|
3/4"
|
14
|
1.041
|
7/8"
|
14
|
1.189
|
1"
|
11
|
1.309
|
1-1/4"
|
11
|
1.650
|
1-1/2"
|
11
|
1.882
|
1-3/4"
|
11
|
2.116
|
2"
|
11
|
2.347
|
2-1/4"
|
11
|
2.587
|
2-1/2"
|
11
|
2.960
|
3"
|
11
|
3.460
|
suggested tap drill sizes
British
Standard Pipe
Parallel or Taper BSP or BSPT |
||||
Nominal Size
(inches) |
T P I
|
Major Diameter
(inches) |
Tapping Drill Size
|
Tapping Drill Size
|
BSP
|
BSPT
|
|||
1/16
|
28
|
0.304
|
6.6
mm
|
|
Letter
drill G
|
||||
1/8
|
28
|
0.383
|
8.8 mm
|
8.4mm
|
11/32
inch
|
21/64"
|
|||
1/4
|
19
|
0.518
|
11.8 mm
|
11.2mm
|
29/64"
|
7/16"
|
|||
3/8
|
19
|
0.656
|
15.25 mm
|
14.75mm
|
19/32"
|
37/64"
|
|||
1/2
|
14
|
0.825
|
19.00mm
|
18.25mm
|
3/4" |
23/32"
|
|||
5/8
|
14
|
0.902
|
21 mm
|
|
53/64"
|
||||
3/4
|
14
|
1.041
|
24.5 mm
|
23.75mm
|
31/32"
|
15/16"
|
|||
7/8
|
14
|
1.189
|
28.25 mm
|
|
1-7/64"
|
||||
1 inch
|
11
|
1.309
|
30.75 mm
|
30mm
|
1-13/64"
|
1-11/64"
|
|||
1-1/4"
|
11
|
1.650
|
39.50 mm
|
38.5mm
|
1-35/64"
|
1-33/64"
|
|||
1-1/2"
|
11
|
1.882
|
45.5 mm
|
44.5mm
|
1-25/32"
|
1-3/4"
|
|||
1-3/4"
|
11
|
2.116
|
51.00 mm
|
|
2"
|
||||
2"
|
11
|
2.347
|
57 mm
|
56mm
|
2-1/4"
|
2-3/16"
|
|||
