Technical Specifications

MILLING CUTTERS

TECHNICAL SUPPLY CONDITIONS OF "DAGGER SCREWING TAPS"
1. Screwing Taps are normally of the non- serial type taps with straight flutes for RH cutting.
2. Serial Taps, Helical flute taps and special taps are manufactured against specific orders.
3. Intermediate size / diameter if ordered, shall be supplied with the same dimensions on the next bigger diameter.
4. other general requirements are maintained according to IS: 6171 - Technical supply conditions for High-speed Screwing Taps.

5. Hardness:
Cutting portion:760 HV to 900Hv
Driving Square: 320 Hv to maximum Hardness equal to cutting Portion (In case of two Piece construction)
5.1 Chamfer Dimensions:

No. of taps in a set	Type of taps chamfer		Chamfer angle	Length (Approx)
No. of taps in a set	Serial	Non-serial	Chamfer angle	Length (Approx)
3 For coarse pitch threads	Rougher intermediate Finisher	Taper Second Bottoming	5 degree 10 degree 20 degree	8 threads 4 threads 2 to 3 threads
2 (For fine pitch)	Rougher Finisher	Tapper Bottoming	7 degree 20 degree	6 threads 2 to 3 threads
1	Nut		2 degree	20 threads

The approximate word indicated in the column heading is not applicable here, as the range has been specified.
5.2 Radial run out when taps are held between centres( T.I.R)

Diameter in mm		Radial runout TIR (Micron)
Above	Up to and including	Taper lead	Thread dia	Shank dia
-	10	30	30	30
10	18	30	30	30
18	30	35	35	40
30	40	40	35	40
40	-	40	40	40

5.3 Taps are usually supplied with a back taper of 1:1000 maximum and the thread diameters are measured on 2nd or 3rd behind the chamfer angle.
5.4 The major diameter and pitch diameter for serial taps are calculated with the following formulas:-

Number of taps in a set	type	Major diameter Min.	Pitch diameter
Number of taps in a set	type	Major diameter Min.	Min	Max
3	Rougher Intermediate Finisher	dB Min - 0.75p dB Min - 0.35p dB Min	d2B Min - 0.25p d2B Min - 0.08p d2B Min	d2B Max - 0.25p d2B Max - 0.08p d2B Max
2	Rougher Finisher	d2B Min - 0.45p db Min	d2B Min - 0.12 d2B Min	d@B Max - 0.12p d2B Max

Where
d2B Min = minimum major diameter of finisher tap
d2B Min = minimum pitch diameter of finisher tap
d2B Max = maximum pitch diameter of finisher tap
p = pitch of threads

6. Serial taps can be supplied in sets or individual pieces as required by the purchaser.
7. Taps are normally supplied with tolerance zone 6H. However taps with other tolerance zone are manufactured against specific order. ISO Metric Taps with thread class 4H are used for tapping internal threads of tolerance zones 4H & 5H recommended for close fit.
Taps with thread tolerance class 6H to be used for tapping internal threads of tolerance Zone 4G, 5G & 6H recommended for medium fit. Taps with thread tolerance class 7H to be used for tapping internal threads of tolerance Zone 6G, 7G & 8H recommended for free fit.
8. Tolerance on threaded portion of taps, other than pipe thread taps, are maintained according to IS 6173 Part 1: 1992
Recommended Rake Angle and Cutting Speed for Taps

Material	Rake Angle	Cutting Speed m/min
Steel up to 50 kg/mm2 Tensile Strength	15-18	7-10
Steel 50-70 kg/mm2 Tensile Strength	12-15	5-8
Steel 70-90 kg/mm2 Tensile Strength	9-12	4-6
Steel (Alloy) 90-100 kg/mm2 Tensile Strength	6-10	2-3
Steel Casting up to 70 kg/mm2 Tensile Strength	12-15	3-5
Malleable Cast iron	6-10	5-8
Cast iron above 200 Be	0-3	2-3
Cast iron soft	3-5	8-10
Stainless steel	10-12	3-5
Brass	0-3	8-10
bronze	6-12	6-8
Copper long Chipped	15-20	8-12
Copper Short Chipped	6-9	8-12
Aluminium	20-25	10-18
Synthetic and plastic material	0-3	3-5

This speed mentioned is recommended speed only. Under favourable and near to ideal working condition , this can be further increased.

CUTTING PARAMETERS IN TAPING & RECOMMENDED CUTTING FLUIDS

The suggested peripheral speed shown in the following table is only starting points which may be varied considerably to suit service conditions.
Tap drill Sizes

Work material	Speed 'Vc'		Cutting Fluids
	Metre/min	Ft/min
Aluminium	15-45	50-150	Kerosene & Lard oil or Kerosene 7 Light oil
Aluminium Bronze	6-24	20-80	Soluble Oil
Bakelite	15-30	50-100	Dry
Brass	15-60	50-200	Soluble Oil or Light Base Oil
Cast iron	15-30	50-100	Dry or Soluble Oil
Copper	9-18	30-60	Mineral Oil with lard or Light Base Oil
Fibre	24-27	80-90	Dry
Magnesium	22-60	75-200	Light Base Oil Diluted with 40% - 50% Kerosene.
Malleable Oil	10-18	35-60	Soluble Oil or Sulphur Base Oil
Magnese Bronze	9-18	30-60	Mineral Oil with lard or Light Base Oil.
Monel metal	6-12	20-40	Sulphur base oil
Naval Brass	24-30	80-100	Mineral Oil with lard or Light Base Oil
Phosphor	9-18	30-60	Mineral Oil with lard or Light Base Oil
Plastics:
Thermo-Plastic	15-30	50-100	Dry or Air jet
Thermo - setting	15-30	50-100	Dry or Air Jet
Steels
Free Machining AISI 1100 Series	18-30	60-100	Soluble or Sulphur Base Oil
Low Carbon(up to to 0.25%)	12-24	60-80	Soluble or Sulphur Base Oil
Medium Carbon Annealed(0.3 to 0.6%)	9-18	830-60	Sulphur Base oil
Heat treated (0.3 to 0.6% carbon) 224 - 283 brinell	7-15	25-50	Chlorinated sulphur base oil
Stainless Steel	1.5 - 10	5-35	Chlorinated sulphur base oil
Titanium alloys	3-12	10-40	Chlorinated sulphur base oil
Zinc-Die Castings	18-45	60-150	Kerosene & lard oil

Recommendations for drills for use prior to tapping ISO metric Screw threads (60 degree Thread Angle)

Tap drill Sizes

Nominal diameter mm	Pitch mm	Drill dia mm
1.00	0.25	0.75
1.10	0.25	0.85
1.20	0.25	0.95
1.40	0.30	1.10
1.60	0.35	1.25
1.80	0.35	1.45
2.00	0.40	1.60
2.20	0.45	1.75
2.50	0.35	2.15
2.50	0.45	2.05
3.00	0.35	2.65
3.00	0.50	2.50
3.50	0.35	3.15
3.50	0.60	2.90
4.00	0.50	3.50
4.00	0.70	3.30
4.50	0.50	4.00
4.50	0.75	3.70
5.00	0.50	4.50
5.00	0.80	4.20
5.50	0.50	5.00
6.00	0.75	5.20
6.00	1.00	5.00
7.00	0.75	6.20
7.00	0.75	6.20
7.00	1.00	6.00
8.00	0.75	7.20
8.00	01.00	7.00
8.00	1.25	6.80
9.00	0.75	8.20
9.00	1.00	8.00
9.00	1.25	7.80
10.00	0.75	9.20
10.00	1.00	9.00
10.00	1.25	8.80
10.00	1.50	8.50
11.00	0.75	10.20
11.00	1.00	10.00
11.00	1.50	9.50

Nominal diameter mm	Pitch mm	Drill dia mm
12.00	1.00	11.00
12.00	1.25	10.80
12.00	1.50	10.50
12.00	1.75	10.20
14.00	1.00	13.00
14.00	1.25	12.80
14.00	1.50	12.50
14.00	2.00	12.00
15.00	1.00	14.00
15.00	1.50	13.50
16.00	1.00	15.00
16.00	1.50	14.50
16.00	2.00	14.00
17.00	1.00	16.00
17.00	1.50	15.50
18.00	1.00	17.00
18.00	1.50	16.50
18.00	2.00	16.00
18.00	2.50	15.50
20.00	1.00	19.00
20.00	1.50	18.50
20.00	2.00	18.00
20.00	2.50	17.50
20.00	1.00	21.00
22.00	1.50	20.50
22.00	2.00	20.00
22.00	2.50	19.50
24.00	1.00	23.00
24.00	1.50	22.50
24.00	2.00	22.00
24.00	3.00	21.00
25.00	1.00	24.00
25.00	1.50	23.50
25.00	2.00	23.00
26.00	1.50	24.50
27.00	1.00	26.00
27.00	1.50	25.50
27.00	2.00	25.00

ISO metric Screw threads(60degree Thread Angle)

Nominal diameter mm	Pitch mm	Drill dia mm
27.00	3.00	24.00
28.00	1.00	27.00
28.00	1.50	26.50
28.00	2.00	26.00
30.00	1.00	29.00
30.00	1.50	28.50
30.00	2.00	28.00
30.00	3.00	27.00
30.00	3.50	26.50
32.00	1.50	30.50
32.00	2.00	30.00
33.00	1.50	31.50
33.00	2.00	31.00
33.00	3.50	29.50
35.00	1.50	33.50
36.00	1.50	34.50
36.00	2.00	34.00
36.00	3.00	33.00
36.00	4.00	32.00
38.00	1.50	36.50
39.00	1.50	37.50
39.00	3.00	36.00
39.00	4.00	35.00
40.00	1.50	38.50
40.00	2.00	38.00
40.00	3.00	37.00

Nominal diameter mm	Pitch mm	Drill dia mm
42.00	1.50	40.50
42.00	2.00	40.00
42.00	3.00	39.00
42.00	4.00	38.00
42.00	4.50	37.50
45.00	1.50	43.50
45.00	2.00	43.00
45.00	3.00	42.00
45.00	4.00	41.00
45.00	4.50	40.50
48.00	1.50	46.50
48.00	2.00	46.00
48.00	3.00	45.00
48.00	4.00	44.00
48.00	5.00	43.00
50.00	1.50	48.50
50.00	2.00	48.00
50.00	3.00	47.00
52.00	1.50	50.50
52.00	2.00	50.00
52.00	3.00	49.00
52.00	4.00	48.00
52.00	5.00	47.00
56.00	5.50	50.50

BSW BRITISH STD. WHITWORTH
Nominal dia mm	TPI	Drill dia mm
1/8	40	2.55
3/16	24	3.7
1/4	20	5.1
5/16	18	6.5
3/8	16	7.9
7/16	14	9.3
1/2	12	10.5
9/16	12	12.1
5/8	11	13.5
11/16	11	15
3/4	10	16.25
7/8	9	19.25
1	8	22
1 1/8	7	24.75
1 1/4	7	28
1 1/2	6	33.5
1 3/4	5	39
2	4.5	44.5
2.1/4	4	51.0
2.1/2	4	57.0
2.3/4	3.5	62.14
3	3.5	68.30

BSW BRITISH STD. FINE
Nominal dia mm	TPI	Drill dia mm
3/16	32	4
7/32	28	4.6
1/4	26	5.3
9/32	26	6.1
5/16	22	6.8
3/8	20	8.3
7/16	18	9.7
1/2	16	11.1
9/16	16	12.7
5/8	14	14
11/16	14	15.5
3/4	12	16.75
7/8	11	19.75
1	10	22.75
1 1/8	9	25.5
1 1/4	9	28.5
1 3/8	8	31.5
1 1/2	8	34.5
1.5/8	8	37.90
1.3/4	7	41.00
2	7	47.00
2.1/4	6	53.00
2.1/2	6	58.00
2.3/4	6	63.35
3	5	69.50

Designating no.	Diameter mm	Pitch mm	Nearest Drill Size
0	6.0	1.00	5.10
1	5.3	0.90	4.50
2	4.7	0.81	4.00
3	4.1	0.73	3.40
4	3.6	0.66	3.00
5	3.2	0.59	2.65
6	2.8	0.53	2.30

Recommendations for drills for use prior to tapping Screw threads BSP (parallel) and BSP (Taper) Form (55 degree Thread angle)BSP(Parallel)

Nominal diameter inch	Thread per inch	Nearest drill size
1/8	28	8.80
1/4	19	11.80
3/8	19	15.25
1/2	14	3/4"
5/8	14	53/64"
3/4	14	24.50
7/8	14	28.25
1	11	30.75
1.1/4	11	39.50
1.1/2	11	1.25/32"
1.3/4	11	51.00
2	11	2.1/4"
2.1/4	11	(63.26)
2.1/2	11	(72.73)
2.3/4	11	(79.08)
3	11	(85.43)
3.1/2	11	(97.88)
4	11	(110.58)

Sizes given with in brackets are hole sizes. Corresponding drill sizes are non- standard.

Recommendations for drills for use prior to tapping Screw threads BSP (parallel) and BSP (Taper) Form
(55 degree Thread angle) BSPT(Taper)

Nominal diameter inch	Thread per inch	Nearest drill size
1/8	28	8.40
1/4	19	11.20
3/8	19	14.75
1/2	14	2.3/32"
3/4	14	15/16"
1	11	30.00
1.1/4	11	38.50
1.1/2	11	44.50
2	11	56.00
2.1/2	11	2.13/16"
3	11	84.35
3	11	84.35"
3.1/2	11	109.42

Recommendations for drills for use prior to tapping Screw threads Parallel) and Taper Pipe

Pipe Threads - taper 'Rc' series(55 degree Thread angle)
Nominal diameter inch	Thread per inch	Hole Diameter Cylinder mm	Hole Diameter Taper mm (Large Dia)
1/8	28	8.3	8.50
1/4	19	11.00	11.40
3/8	19	14.50	14.90
1/2	14	18.10	18.50
3/4	14	23.50	24.00
1	11	29.60	30.10
1.1/4	11	38.10	38.80
1.1/2	11	44.00	44.70
2	11	56.00	56.50

Pipe Threads - taper 'Rc' series(60 degree Thread angle)
Nominal diameter inch	Thread per inch	Hole Diameter Taper mm
1/8	28	8.60
1/4	19	11.50
3/8	19	15.00
1/2	14	18.50
3/4	14	24.00
1	11	30.25
1.1/4	11	39.00
1.1/2	11	45.00
2	11	56.50
-	-	-

Pipe Threads - taper 'Rc' series(55 degree Thread angle)
Nominal diameter inch	Thread per inch	Hole Diameter Cylinder mm	Hole Diameter Taper mm (Large Dia)
1/8	28	8.3	8.50
1/4	19	11.00	11.40
3/8	19	14.50	14.90
1/2	14	18.10	18.50
3/4	14	23.50	24.00
1	11	29.60	30.10
1.1/4	11	38.10	38.80
1.1/2	11	44.00	44.70
2	11	56.00	56.50

American National taper Pipe Hand Taps(NPT) (60 degree Thread angle)
Nominal diameter inch	Thread per inch	Hole Diameter Taper mm	Hole Diameter Taper mm large Dia
1/8	27	8.5	8.70
1/4	18	11.00	11.30
3/8	18	14.40	14.70
1/2	14	17.80	18.20
3/4	14	23.10	23.60
1	11 1/2	29.10	29.60
1.1/4	11/12	37.80	38.50
1.1/2	11 1/2	43.90	44.40
2	11 1/2	43.90	44.40
2	11 1/2	55.90	56.40

Pipe Threads- Parallel 'G' series (60 degree Thread angle)
Nominal diameter inch	Thread per inch	Hole Diameter Taper mm
1/8	28	8.80
1/4	18	11.80
3/8	19	15.25
1/2	14	19.00
5/8	14	21.00
3/4	14	24.50
7/8	14	28.25
1	11	30.75
1 1/4	11	39.50
1 1/2	11	45.00
1 3/4	11	51.00
2	11	57.00

Recommendations for Drills
for use prior to tapping Screw thread
UNC and UNF Form
(60 degree thread angle)

UNC UNIFIED COARSE
Nominal diameter inch	Thread per inch	Drill Dia mm
No.1	64.00	1.55
No.2	56.00	1.85
No.3	48.00	2.10
No.4	40.00	2.35
No.5	40.00	2.65
No.6	32.00	2.85
No.8	32.00	3.50
No.10	24.00	3.90
No. 12	24.00	4.50
1/4	20.00	5.10
5/16	18.00	6.60
3/8	16.00	8.00
7/16	14.0	9.40
1/2	13.00	10.80
9/16	12.00	12.20
5/8	11.00	13.50
3/4	10.00	16.50
7/8	9.00	19.50
1	8.00	22.25
1 1/8	7.00	25.00
1 1/8	7.00	28.00
1.3/8	6.00	30.75
1 1/2	6.00	34.00
1 3/4	5.00	39.50
2	4.50	45.00

UNF UNIFIED FIne
Nominal diameter inch	Thread per inch	Drill Dia mm
No. 0	80	1.25
No. 1	72	1.55
No. 2	64	1.90
No. 3	56	2.15
No. 4	48	2.40
No. 5	44	2.70
No. 6	40	2.95
No. 8	36	3.50
No. 10	32	4.10
No. 12	28	4.70
1/4	28	5.50
5/16	24	6.90
3/8	24	8.50
7/16	20	9.90
1/2	20	11.50
9/16	18	12.90
5/8	18	14.50
3/4	16	17.50
7/8	14	20.40
1	12	23.25
1 1/8	12	26.50
1 1/4	12	29.50
1 3/8	12	32.75
1 1/2	12	36.00
-	-	-

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