A25-TAP_EU-EN

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

Tap Drill Information and Formulas | Imperial (inch)

A

American - Unified Inch Screw Thread

Formulas

1. RPM

= (3.82 • SFM) / DIA

Probable Mean Oversize

where: RPM = revolutions per minute (rev/min) SFM = speed (ft/min) DIA = diameter of drill (inch) 2. IPM = RPM • IPR where: IPM = inches per minute (in/min) RPM = revolutions per minute (rev/min) IPR = feed rate (in/rev)

Tap Drill Size

Decimal Equivalent

* Theo % Thread

Probable Hole Size

** Probable % Thread

DRILLING

Tap Size 1/2 - 20

29/64

0.4531

72% 72% 83% 87% 70% 65% 79% 72% 87% 75% 65% 72% 84% 77% 72% 72% 77% 75% 76% 65% 84% 67% 72% 72% 82% 77% 67% 87% 72% 67% 87% 72% 76%

0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003

0.4561 0.4754 0.4874 0.5030 0.5148 0.5186 0.5343 0.5499 0.5655 0.5739 0.5811 0.6124 0.6436 0.6526 0.6593 0.6749 0.6905 0.6920 0.7686 0.7843 0.7999 0.8155 0.8624 0.8936 0.8691 0.8780 0.8936 0.9093 0.9249 0.9405 1.0343 1.0499 1.1124

68% 69% 80% 82% 66% 61% 77% 69% 82% 71% 61% 69% 82% 75% 70% 69% 73% 71% 74% 63% 81% 64% 69% 68% 81% 75% 65% 84% 69% 64% 84% 69% 74%

12.0 mm 0.4724

9/16 - 12

31/64

0.4844 0.5000

1/2

9/16 - 18

13.0 mm 0.5118

31/64 17/32 35/64

0.5156 0.5313 0.5469 0.5625 0.5781 0.6094 0.6406 0.6563 0.6719 0.6875 0.7656 0.7813 0.7969 0.8125 0.8594 0.8906 0.8750 0.8906 0.9063 0.9219 0.9375 1.0313 1.0469 1.1094

5/8 - 11 5/8 - 12

B

9/16

3. SFM

= RPM • 0.262 • DIA

5/8 - 18

14.5 mm 0.5709

where: SFM = speed (ft/min) RPM = revolutions per minute (rev/min) DIA = diameter of drill (inch)

37/64

11/16 - 12 39/64

BORING

41/64

3/4 - 10

16.5 mm 0.6496

21/32 43/64 11/16 49/64 25/32 51/64 13/16

4. Thrust

= 153,700 • IPR • DIA • K m

3/4 - 12

where: Thrust

3/4 - 16

= axial thrust (lbs) = feed rate (in/rev)

17.5 mm 0.6890

IPR DIA

7/8 - 9

= diameter of drill (inch)

K m

= specific cutting energy (lbs/in 2 )

C

7/8 - 14

5. Tool Power = .6991 • IPR • RPM • K m • DIA 2 where: Tool Power = tool power (HP) IPR = feed rate (in/rev) RPM = revolutions per minute (rev/min) K m = specific cutting energy (lbs/in 2 ) DIA = diameter of drill (inch)

15/16 - 12 55/64 15/16 - 20 57/64

REAMING

22.0 mm 0.8661

1 - 8

7/8

57/64 29/32 59/64 15/16 1-1/32 1-3/64 1-7/64

1 - 12

1 - 14

1-1/8 - 12

1-1/4 - 7

D

BURNISHING

Material Constants

Taper Pipe Thread (NPT)

Probable Mean Oversize

K m (lbs/in 2 )

Tap Drill Size

Decimal Equivalent

* Theo % Thread

Probable Hole Size

** Probable % Thread

Type of Material

Hardness

Tap Size 1/4 - 18 3/8 - 18 1/2 - 14 3/4 - 14

Plain Carbon and Alloy Steel

85 - 200 BHN 0.79 200 - 275 BHN 0.94 275 - 375 BHN 1.00 375 - 425 BHN 1.15

7/16 9/16

0.4375 0.5625 0.7031 0.9063

- - - -

0.003 0.003 0.003 0.003

0.4405 0.5655 0.7061 0.9093

- - - -

E

45/64 29/32

High-Temperature Alloys

- -

1.44 0.72

* Based on nominal tap drill diameter ** Based on 0.003" probable mean oversize

THREADING

Titanium Alloy Stainless Steels

135 - 275 BHN 0.94 30 - 45 RC 1.08 100 - 200 BHN 0.50 200 - 300 BHN 1.08

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

Cast Iron

(Basic major diameter of thread - Drill hole size) .0130

Copper Alloy

20 - 80 RB 80 - 100 RB

0.43 0.72 0.22 0.16

% Thread =

# of threads per inch •

Aluminium 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 0.003" 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

www.alliedmachine.com | +44 (0) 1384 400 900 | enquiries.eu@alliedmachine.com

A25: 67