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DRILLING | T-A Pro® High Penetration Replaceable Insert Drilling System

Tap Drill Information and Formulas | Metric (mm)

A

Formulas 1. RPM = (318.47 • m/min) / DIA where:

DRILLING

Decimal Equivalent (inch)

Probable Mean Oversize

Tap Drill Size

* Theo % Thread

Probable Hole Size

** Probable % Thread

RPM = revolutions per minute (rev/min) m/min = speed (m/min) DIA = diameter of drill (mm) 2. mm/min = RPM • mm/rev where: mm/min = mm per minute (mm/min) RPM = revolutions per minute (rev/min) mm/rev = feed rate (mm/rev)

Tap Size

27/64

0.4219

79% 0.075 mm 10.79 mm 74% 74% 0.075 mm 10.88 mm 69% 81% 0.075 mm 11.98 mm 78% 77% 0.075 mm 12.08 mm 74% 77% 0.075 mm 12.58 mm 73% 77% 0.075 mm 14.08 mm 74% 77% 0.075 mm 14.58 mm 73% 68% 0.075 mm 14.76 mm 64% 77% 0.075 mm 15.58 mm 75% 77% 0.075 mm 16.58 mm 73% 68% 0.075 mm 16.75 mm 64% 78% 0.075 mm 17.54 mm 76% 77% 0.075 mm 17.58 mm 74% 77% 0.075 mm 18.58 mm 73% 69% 0.075 mm 18.66 mm 65% 79% 0.075 mm 19.52 mm 76% 77% 0.075 mm 19.58 mm 75% 77% 0.075 mm 20.58 mm 73% 70% 0.075 mm 20.71 mm 66% 86% 0.075 mm 20.71 mm 84% 76% 0.075 mm 21.08 mm 75% 77% 0.075 mm 22.08 mm 74% 68% 0.075 mm 22.30 mm 65% 77% 0.075 mm 24.08 mm 75%

12 X 1.25

10.8 mm 0.4252

15/32

0.4688

14 X 2.0

12.0 mm 0.4724

14 X 1.5 12.5 mm 0.4921 16 X 2.0 14.0 mm 0.5512

B

14.5 mm 0.5709

16 X 1.5

37/64

0.5781

18 X 2.5 15.5 mm 0.6102

BORING

3. m/min

= RPM • 0.003 • DIA

16.5 mm 0.6496

18 X 1.5

where: m/min

21/32 11/16

0.6563 0.6875

= speed (m/min) RPM = revolutions per minute (rev/min) DIA = diameter of drill (mm)

20 X 2.5

17.5 mm 0.6890 18.5 mm 0.7283

20 X 1.5

47/64 49/64

0.7344 0.7656

4. Thrust

= 154 • (mm/rev) • DIA • K m

22 X 2.5

where: Thrust mm/rev

19.5 mm 0.7677 20.5 mm 0.8071

= axial thrust (N)

C

22 X 1.5

= feed rate (mm/rev) = diameter of drill (mm)

13/16 13/16

0.8125 0.8125

DIA

24 X 3

K m

= specific cutting energy (kPa)

21.0 mm 0.8268 22.0 mm 0.8661

REAMING

24 X 2

5. Tool Power

= ((mm/rev) • RPM • K m • DIA

2 ) / 218604.8

7/8

0.8750

where: Tool Power = tool power (HP) mm/rev = feed rate (mm/rev) RPM = revolutions per minute (rev/min) K m = specific cutting energy (kPa) DIA = diameter of drill (mm)

27 X 3

24.0 mm 0.9449

D

BURNISHING

BSP and ISO 7-1

Material Constants

Probable Mean Oversize

Tap Drill Size

Decimal Equivalent

* Theo % Thread

Probable Hole Size

** Probable % Thread

K m (kPa)

Tap Size

Type of Material

Hardness

Plain Carbon and Alloy Steel

1/4-19 3/8-19 1/2-14 3/4-14

7/16

0.4375 0.5781 0.7188 0.9375

- - - -

0.075mm 11.19 mm - 0.075mm 14.76 mm - 0.075mm 18.33 mm - 0.075mm 23.89 mm -

85 - 200 BHN 5.45 200 - 275 BHN 6.48 275 - 375 BHN 6.89 375 - 425 BHN 7.93

37/64 23/32 15/16

E

High-Temperature Alloys

- -

9.93 4.96

*Based on nominal tap drill diameter. **Based on 0.075 mm probable mean oversize.

Titanium Alloy Stainless Steels

THREADING

135 - 275 BHN 6.48 30 - 45 RC 7.45 100 - 200 BHN 3.45 200 - 300 BHN 7.45

To calculate the percent of full thread for a given hole diameter:

Cast Iron

Copper Alloy

20 - 80 RB 80 - 100 RB

2.96 4.96 1.52 1.10

76.93

% Thread =

• (Basic major diameter - Drill hole size)

Pitch (mm)

Aluminum Alloy Magnesium Alloy

- -

X

Notes • The above tap drill information represents probable thread percentages for the standard tap drills stocked at Allied Machine. Special insert diameters may be required in order to meet a user specific percentage of thread requirement. • The 0.075 mm probable mean oversize hole condition is based on optimum cutting conditions. Probable percent of full thread may vary based on less ideal cutting conditions. • The table and equations on this page are found in the Machinery’s Handbook . Permission to simplify and print the equations is granted by the editor of the Machinery’s Handbook .

SPECIALS

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