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DRILLING | T-A® Replaceable Insert Drilling System

T-A®: Tap Drill Information and Formulas | Metric (mm)

XTP TAP TAS HPU APX 4TX REV OPN SSD ACP BTA WHL CRT ALV BRN THM

Metric Profile Screw Thread

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

Probable Mean Oversize

Tap Drill Size 10.2 mm

Decimal Equivalent

* Theo % Thread

Probable Hole Size

** Probable % Thread

= revolutions per minute (rev/min)

Tap Size 12 x 1.75

M/min

= speed (M/min)

0.4016" 0.4063" 0.4219" 0.4252" 0.4688" 0.4724" 0.4921" 0.5512" 0.5709" 0.5781" 0.6102" 0.6496" 0.6563" 0.6875" 0.6890" 0.7283" 0.7344" 0.7656" 0.7677" 0.8071" 0.8125" 0.8125" 0.8268" 0.8661" 0.8750" 0.9449"

79% 0.075 mm 10.28 mm 76% 74% 0.075 mm 10.40 mm 71% 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% 0.07 5mm 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%

DIA

= diameter of drill (mm)

12 x 1.75 13/32" 12 x 1.25 27/64"

2. mm/min = RPM • mm/rev where: mm/min

12 x 1.25 14 x 20 14 x 20 14 x 1.5 16 x 2.0 16 x 1.5 16 x 1.5 18 x 2.5 18 x 1.5 18 x 1.5 20 x 2.5 20 x 2.5 20 x 1.5 20 x 1.5 22 x 2.5 22 x 2.5 22 x 1.5 22 x 1.5

10.8 mm

15/32"

= mm per minute (mm/min)

12.0 mm 12.5 mm 14.0 mm 14.5 mm

RPM

= revolutions per minute (rev/min)

mm/rev

= feed rate (mm/rev)

3. M/min

= RPM • 0.003 • DIA

37/64"

where: M/min

15.5 mm 16.5 mm

= speed (M/min)

RPM

= revolutions per minute (rev/min)

21/32" 11/16"

DIA

= diameter of drill (mm)

17.5 mm 18.5 mm

4. Thrust

= 154 • (mm/rev) • DIA • K m

where: Thrust mm/rev

47/64" 49/64"

= axial thrust (N)

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

19.5 mm 20.5 mm

DIA

K m

= specific cutting energy (bar)

13/16" 13/16"

24 x 3 24 x 3 24 x 2 24 x 2 27 x 3

5. Tool Power

= ((mm/rev) • RPM • K m • DIA

2 ) / 210604.8

21.0 mm 22.0 mm

where: Tool Power

= tool power (HP) = feed rate (mm/rev)

7/8"

mm/rev

24.0 mm

RPM

= revolutions per minute (rev/min) = specific cutting energy (bar)

K m

DIA

= diameter of drill (mm)

Taper Pipe Thread (NPT)

Material Constants

Probable Mean Oversize

Tap Drill Size

Decimal Equivalent

Theo % Thread*

Probable Hole Size

Probable % Thread**

K m (kPa) 5.45 6.48 6.89 7.93 9.93 6.48 7.45 3.45 7.45 2.96 4.96 4.96 1.52 1.10

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

Type of Material

Hardness

7/16 9/16

0.4375 0.5625 0.7031 0.9063

- - - -

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

Plain Carbon and Alloy

85 - 200 BHN 200 - 275 BHN 275 - 375 BHN 375 - 425 BHN

Steel

45/64 29/32

High-Temperature Alloys

-

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

Stainless Steels

135 - 275 BHN

30 - 45 RC

Cast Iron

100 - 200 BHN 200 - 300 BHN

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

Copper Alloy

20 - 80 RB 80 - 100 RB

76.93 Pitch (mm)

Titanium Alloy Aluminum Alloy Magnesium Alloy

- - -

Basic Major Diameter of Thread (mm) - Drill Hole Size (mm)

% Thread =

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 requirements. • 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 .

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