WORKSHOP TABLES

Here are some useful tables for the modellers workshop.

Contents

Number and Letter drill sizes ....... equivalent metric and decimal inches

Drill No.

Decimal inch

metric mm

Drill No./Letter

decimal inch

metric mm

80

0.013

0.3302

27

0.144

3.6576

79

0.014

0.3556

26

0.147

3.7338

78

0.015

0.3810

25

0.1495

3.7973

77

0.016

0.4064

24

0.152

3.8608

76

0.018

0.4572

23

0.154

3.9116

75

0.020

0.5080

22

0.157

3.9878

74

0.022

0.5588

21

0.159

4.0386

73

0.023

0.5842

20

0.161

4.0894

72

0.024

0.6096

19

0.166

4.2164

71

0.026

0.6604

18

0.1695

4.3053

70

0.027

0.6858

17

0.173

4.3942

69

0.029

0.7366

16

0.177

4.4958

68

0.030

0.7620

15

0.180

4.5720

67

0.031

0.7874

14

0.182

4.6228

66

0.032

0.8128

13

0.185

4.6990

65

0.033

0.8382

12

0.189

4.8006

64

0.035

0.8890

11

0.191

4.8514

63

0.036

0.9144

10

0.1935

4.9149

62

0.037

0.9398

9

0.196

4.9784

61

0.038

0.9652

8

0.199

5.0546

60

0.039

0.9906

7

0.201

5.1054

59

0.041

1.0414

6

0.204

5.1816

58

0.042

1.0668

5

0.2055

5.2197

57

0.043

1.0922

4

0.209

5.3086

56

0.0465

1.1811

3

0.213

5.4102

55

0.052

1.3208

2

0.221

5.6134

54

0.055

1.3970

1

0.228

5.7912

53

0.0595

1.5113

A

0.234

5.9436

52

0.0635

1.6129

B

0.238

6.0452

51

0.067

1.7018

C

0.242

6.1468

50

0.070

1.7780

D

0.246

6.2484

49

0.073

1.8542

E

0.250

6.3500

48

0.076

1.9304

F

0.257

6.5278

47

0.0785

1.9939

G

0.261

6.6294

46

0.081

2.0574

H

0.266

6.7564

45

0.082

2.0828

I

0.272

6.9088

44

0.086

2.1844

J

0.277

7.0358

43

0.089

2.2606

K

0.281

7.1374

42

0.0935

2.3749

L

0.290

7.3660

41

0.096

2.4384

M

0.295

7.4930

40

0.098

2.4892

N

0.302

7.6708

39

0.0995

2.5273

O

0.316

8.0264

38

0.1015

2.5781

P

0.323

8.2042

37

0.104

2.6416

Q

0.332

8.4328

36

0.1065

2.7051

R

0.339

8.6106

35

0.110

2.7940

S

0.348

8.8392

34

0.111

2.8194

T

0.358

9.0932

33

0.113

2.8702

U

0.368

9.3472

32

0.116

2.9464

V

0.377

9.5758

31

0.120

3.0480

W

0.386

9.8044

30

0.1285

3.2639

X

0.397

10.0838

29

0.136

3.4544

Y

0.404

10.2616

28

0.1405

3.5687

Z

0.413

10.4902

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BA Standard Threads and Tap Drill Sizes

Number

Pitch mm.

Pitch inch (app)

O/D inches

O/D mm

Tap Drill Size

Tap Drill Size Metric

Clearance size

Clearance size Metric

0

1.000

0.0394

0.236

5.9944

12

5.1

B

6.1

1

0.900

0.0354

0.208

5.2832

19

4.5

3

5.4

2

0.810

0.0319

0.185

4.6990

26

4

3/16

4.8

3

0.730

0.0287

0.161

4.0894

29

3.45

19

4.2

4

0.660

0.0260

0.142

3.6068

33

3

27

3.7

5

0.590

0.0232

0.126

3.2004

39

2.65

30

3.3

6

0.530

0.0209

0.110

2.7940

43

2.3

34

2.85

7

0.480

0.0189

0.098

2.4892

47

2.05

39

2.55

8

0.430

0.0169

0.087

2.2098

50

1.8

43

2.3

9

0.390

0.0154

0.075

1.9050

1/16

1.55

48

1.95

10

0.350

0.0138

0.067

1.7018

54

1.4

50

1.75

11

0.310

0.0122

0.059

1.4986

56

1.2

53

1.6

12

0.280

0.0110

0.051

1.2954

61

1.05

55

1.4

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Model Engineer ( M.E.) threads and tap drill sizes

Diameter

TPI

Tap drill (metric)

Tap drill

Clearance (metric)

Clearance Outside

1/8

40

2.40

3/32

3.30

No. 30

5/32

40

3.25

No. 30

4.2

No. 19

3/16

40

3.90

No. 23

5.00

No. 10

7/32

40

4.75

No. 13

5.8

No. 1

1/4

32

5.6

No. 2

6.6

G

1/4

40

5.5

No. 3

6.6

G

9/32

32

6.6

G

7.2

9/32

9/32

40

6.5

F

7.2

9/32

5/16

32

7.0

J

8.2

P

5/16

40

7.3

L

8.2

P

3/8

32

8.6

R

9.8

W

3/8

40

8.9

S

9.8

W

7/16

32

10.3

Y

11.4

29/64

7/16

40

10.5

Z

11.4

29/64

1/2

32

11.9

15/32

13

33/64

1/2

40

12.1

15/32

13

33/64

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Lathe cutting speeds


Material Group A B C D E
Type of Cut Rough Finish Rough Finish Rough Finish Rough Finish Rough Finish
Diameter(inch) RPM
1/8 610 760 1225 1525 2000 2300 3600 4275 - -
1/4 305 380 610 765 995 1150 1830 2140 - -
3/8 205 250 405 500 660 760 1220 1425 - -
1/2 175 190 305 380 500 570 920 1070 - -
5/8 125 150 245 305 400 460 730 855 3700 5000
3/4 100 127 205 250 330 380 610 715 3050 4000
1 75 95 150 190 250 285 460 535 2300 3000
1 1/4 60 75 125 190 200 230 360 430 1840 2500
1 1/2 50 64 100 125 165 190 310 360 1540 2000
1 3/4 45 55 85 110 140 165 260 305 1300 1700
2 38 48 76 95 125 145 230 270 1150 1530
3 26 32 51 63 82 95 150 180 760 1000
4 19 24 38 48 62 71 114 135 570 760
5 - - 30 38 50 57 91 105 460 600
6 - - 25 32 41 47 75 82 380 500
7 - - 22 28 36 42 67 78 335 450
8 - - - - 31 36 58 67 290 380
9 - - - - 27 32 50 59 250 340
10 - - - - 25 28 45 53 225 300
MATERIALS
Cast Iron (hard) Cast steel anneald Bakelite Brass (common) Aluminium
Maleable iron Bronze Muntz metal Duralumin
Monel metal Cast iron (ordinary) Steel (freecutting) Tufnol
Stainless steel Copper (drawn)
Sliver steel Gunmetal
Phos. bronze
Black or BDMS steel
TOOLS Carbon steel tools only use 2/3 of the above speeds
Carbide tools increase the speeds by 50% to 70%
Parting off reduce speeds by 75%
Tools assumed are 5/16 or 3/8 shanked


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Drilling Speeds

Drill Diameter Materials Group
Inch mm A B C D E
1/32 0.75 4900 - - - -
1/16 1.5 2455 4300 - - -
1/8 3.0 1220 2140 3100 4500 -
3/16 4.75 815 1430 2040 3060 4900
1/4 6.5 600 1070 1530 2300 3650
5/16 8.5 490 850 1220 1800 2950
3/8 9.5 410 710 1020 1530 2450
7/16 11.0 350 610 870 1300 2100
1/2 12.5 310 535 760 1140 1850
9/16 14.0 270 475 670 1010 1600
5/8 16.0 245 430 610 910 1450
11/16 17.5 220 390 550 830 1300
3/4 19.0 205 360 500 760 1220
7/8 22.0 175 300 430 650 1050
1 25.5 150 265 380 570 900
Materials

Cast iron (hard)

Cast Steel (annealed)

 Bakelite

Brass (common)

 Aluminium
Maleable iron Bronze Muntz Metal Duralumin
Monel metal Cast iron (ordinary) Steel (freecutting) Tufnel
Stainless Steel Copper (drawn)
Silver steel Gun metal
Phos. Bronze
Black or BDMS steel
Material Point Angle Helix Remarks
Aluminium, Copper, Light Alloy 100 Quick  
High Tensile Steel 130 Slow  
Cast Iron 90 to 118 Standard  
Plastics 90 Standard Use narrow land
Brass 118 Slow Reduce top rake to 0

 

 

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End mill Speeds

NOTE: speeds are for depth of cut=1/8 diameter up to 3/16 then =1/4 diameter. Width of cut up to 1/4 diameter. Cutter is HSS four flute.

 

Cutter diameter(Inches)

 1/16 3/32 1/8 3/16 1/4 3/8 1/2 5/8 3/4
Speeds rpm                  
Mild Steel 1800 1500 1200 800 650 450 350 250 180
Brass 2500 2000 1600 1150 850 650 450 350 250
Alloy 3500 3000 2500 1700 1400 1200 900 800 700

 

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Slot Drill Speeds

 

 

Cutter diameter (inches) 1/16 3/32 1/8 3/16 1/4 3/8 1/2 5/8 3/4
Speeds rpm
Mild Steel 2000 1500 1200 800 600 400 300 240 180
Brass and Alloy 8000* 7500* 7000* 6500* 4500 3500 2200 1800 1000
Note: Brass and Alloy marked * maximum available

 

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Standard Wire Gauges

Wire Gauge
Inches
Wire Gauge
Inches
6/0 0.464
26
 0.018
5/0 0.432
27
 0.0164
4/0 0.400
28
 0.0148
3/0 0.372
29
 0.0136
2/0 0.348
30
 0.0124
0 0.342
31
 0.0116
1
0.300
32
0.0108
2
0.276
33
0.0100
3
0.252
34
0.0092
4
0.232
35
0.0084
5
0.212
36
0.0076
6
0.192
37
0.0068
7
0.176
38
0.0060
8
0.160
39
0.0052
9
0.144
40
0.0048
10
0.128
41
0.0044
11
0.116
42
0.0040
12
0.104
43
0.0036
13
0.092
44
0.0032
14
0.080
45
0.0028
15
0.072
46
0.0024
16
0.064
47
0.0020
17
0.056
48
0.0016
18
0.048
 49
0.0012
19
0.040
50
0.0010
20
0.038
21
0.032
22
0.028
23
0.024
24 0.022
25
0.020

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Morse Tapers

No. of Taper Taper/inch on diameter (inch) Taper/foot Included angle
0 0.05205 0.624600
1 0.04988 0.59858
2 0.04995 0.59941
3 0.05020 0.60235
4 0.05194 0.62326
5 0.05263 0.63151
6 0.05214 0.62565
7 0.05200 0.62400

Note 1: A morse taper is "about" 5/8" per foot. No doubt historically it was intended to be exactly 5/8" per foot but as standard masters were produced from which to gauge manufacturing those master were not made precisely the same as now can be measured by modern equipment. So all morse tapers have to be made to these old dimensions otherwise they would not fit machines and be interchangeable.

Note 2: The taper is measured on the full diameter i.e the length it takes to go from zero to full diameter expressed as an increase per inch or per foot. The included angle is the angle opposite the the full diameter. The angle set on the top slide for turning is thus HALF the included angle.

EXAMPLE: No2 Morse taper the diameter is increased by 0.04995" over a length of 1" so the included angle can be found from taper/inch= TAN 1/2(included angle)

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