A30-TAS_EU-EN
DRILLING | T-A® Replaceable Insert Drilling System
Tap Drill Information and Formulas | Imperial (inch)
A
American - Unified Inch Screw Thread
Formulas 1. RPM = (3.82 • SFM) / DIA where: RPM
Probable Mean Oversize
Tap Drill Size
Decimal Equivalent
* Theo % Thread
Probable Hole Size 0.3890" 0.3936" 0.4164" 0.4249" 0.4405" 0.4561" 0.4718" 0.4874" 0.4754" 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" 0.8780" 0.9403"
** Probable % Thread
Tap Size 7/16 - 20
DRILLING
= revolutions per minute (rev/min)
W 0.3860
79% 72% 87% 78% 63% 72% 87% 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% 68% 77%
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" 0.003" 0.003" 0.003" 0.003" 0.003" 0.003" 0.003" 0.003"
75% 68% 84% 75% 60% 68% 84% 69% 80% 82% 66% 61% 77% 69% 82% 75% 70% 69% 82% 75% 70% 69% 73% 71% 74% 63% 81% 64% 69% 68% 81% 75% 65% 84% 69% 64% 84% 69% 74% 65% 75%
SFM
= speed (ft/min)
7/16 - 20 25/64"
0.3906
DIA
= diameter of drill (inch)
1/2 - 13 10.5 mm 0.4134
1/2 - 13 1/2 - 13 1/2 - 20
27/64"
0.4219 0.4375 0.4531 0.4688 0.4844 0.5000" 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" 0.8750"
2. IPM = RPM • IPR where: IPM
7/16"
29/64"
= inches per minute (in/min)
9/16 - 12 15/32"
RPM
= revolutions per minute (rev/min)
9/16 - 12 12.0 mm 0.4724
IPR
= feed rate (in/rev)
9/16 - 12 31/64"
B
9/16 - 18
1/2"
3. SFM = RPM • 0.262 • DIA where: SFM = speed (ft/min) RPM
9/16 - 18 13.0 mm 0.5118"
9/16 - 18 31/64"
5/8 - 11 5/8 - 12 5/8 - 18
17/32" 35/64"
BORING
= revolutions per minute (rev/min)
DIA
= diameter of drill (inch)
9/16"
5/8 - 18 14.5 mm 0.5709"
5/8 - 18
37/64"
4. Thrust
= 153,700 • IPR • DIA • K m
11/16 - 12 39/64"
where: Thrust
3/4 - 10
41/64"
= axial thrust (lbs) = feed rate (in/rev)
3/4 - 10 16.5 mm 0.6496"
IPR DIA
3/4 - 10 3/4 - 12 3/4 - 16 7/8 - 9 7/8 - 9 7/8 - 14 7/8 - 14
21/32" 43/64" 11/16" 49/64" 25/32" 51/64" 13/16"
= diameter of drill (inch)
K m
= specific cutting energy (lbs/in 2 )
C
3/4 - 16 17.5 mm 0.6890"
5. Tool Power = .6283 • 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)
REAMING
15/16 - 12 55/64" 15/16 - 20 57/64"
1 - 8 1 - 8 1 - 8
22.0 mm 0.8661"
7/8"
57/64" 29/32" 59/64" 15/16"
1 - 12 1 - 12 1 - 14
Material Constants
D
K m (lbs/in 2 )
1-1/8 - 12 1-1/32" 1-1/8 - 12 1-3/64" 1-1/4 - 7 1-7/64"
Type of Material
Hardness
BURNISHING
Plain Carbon and Alloy
85 - 200 BHN 0.79 200 - 275 BHN 0.94 275 - 375 BHN 1.00 375 - 425 BHN 1.15 135 - 275 BHN 0.94 30 - 45 RC 1.08 100 - 200 BHN 0.50 200 - 300 BHN 1.08 - 1.44
24 x 2 27 x 3
7/8"
Steel
24.0 mm 0.9449"
Taper Pipe Thread (NPT)
High-Temperature Alloys
Probable Mean Oversize
Stainless Steels
Tap Drill Size
Decimal Equivalent
Theo % Thread*
Probable Hole Size
Probable % Thread**
Tap Size 1/4 - 18 3/8 - 18 1/2 - 14 3/4 - 14
Cast Iron
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
- - - -
Copper Alloy
20 - 80 RB 80 - 100 RB
0.43 0.72 0.72 0.22 0.16
45/64 29/32
E
Titanium Alloy Aluminium Alloy Magnesium Alloy
- - -
* Based on nominal tap drill diameter ** Based on 0.003" probable mean oversize
THREADING
To calculate the percent of full thread for a given hole diameter:
Basic Major Diameter of Thread - Drill Hole Size 0.0130
% Thread =
# of Thread per Inch
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 requirements. • 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
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