Thread data sheet

Basic Thread Dimensions

Property Inch mm
Nominal Diameter 0.086 2.184
Pitch (TPI)56
Pitch (Distance) 0.0179 0.455
Pitch Diameter 0.0744 1.89
Minor Diameter 0.0647 1.643
Thread Height 0.0097 0.246
Addendum 0.0058 0.147
Crest (External)
Root (Internal)
0.0022 0.056
Tap Drill Size
(75% depth)
0.069 1.74
Lead Angle
(Single Start)
4.38°
Thread Family Unified Coarse Pitch (UNC)
Relevant Standards ASME B1.1-2003
Equivalent MetricThreadM2.2

For more threading data scroll down, or use the Thread Calculator

Choose the Threading Data you want to explore


#2 - 56 UNCPossible Thread Classes

External Threads

2A, 3A

Metric ISO External Thread - Tolerance sketch

Internal Threads

2B, 3B

Metric ISO Internal Thread - Tolerance sketch

#2 - 56 UNC 2A (External)

* Permisable values for thread Class 2A

# Description Value (Inch) Value (mm)
es Allowance 0.0006 (Ref) 0.015 (Ref)
d Major Diameter 0.0813 - 0.0854 2.065 - 2.169
d2 Pitch Diameter 0.0717 - 0.0738 1.821 - 1.875
d3 Minor Diameter
(UNR Only)
0.0641 (Ref) 1.628 (Ref)
α Varation of 30° anngle (+/-) 2.25°
P Varation of pitch (+/-) 0.0006 (Ref) 0.015 (Ref)

* Values are calculated for Length of engagement of 5xPitch. For calculations of different engagement length use the Thread Calculator'

* Back to Thread Class Selection


#2 - 56 UNC 3A (External)

* Permisable values for thread Class 3A

# Description Value (Inch) Value (mm)
es Allowance 0 (Ref) 0 (Ref)
d Major Diameter 0.0819 - 0.086 2.08 - 2.184
d2 Pitch Diameter 0.0728 - 0.0744 1.849 - 1.89
d3 Minor Diameter
(UNR Only)
0.0647 (Ref) 1.643 (Ref)
α Varation of 30° anngle (+/-) 2.25°
P Varation of pitch (+/-) 0.0005 (Ref) 0.013 (Ref)

* Values are calculated for Length of engagement of 5xPitch. For calculations of different engagement length use the Thread Calculator'

* Back to Thread Class Selection


#2 - 56 UNC 2B (Internal)

* Permisable values for thread Class 2B

# Description Value (Inch) VValue (mm)
D1 Minor Diameter 0.0667 - 0.0737 1.694 - 1.872
D2 Pitch Diameter 0.0744 - 0.0772 1.89 - 1.961
D Major Diameter 0.0860 (Min) 2.184 (Min)
α Varation of 30° anngle (+/-) 2.25°
P Varation of Pitch (+/-) 0.0008 (Ref) 0.02 (Ref)

* Values are calculated for Length of engagement of 5xPitch. For calculations of different engagement length use the Thread Calculator

* Back to Thread Class Selection


#2 - 56 UNC 3B (Internal)

* Permisable values for thread Class 3B

# Description Value (Inch) VValue (mm)
D1 Minor Diameter 0.0667 - 0.0737 1.694 - 1.872
D2 Pitch Diameter 0.0744 - 0.0765 1.89 - 1.943
D Major Diameter 0.0860 (Min) 2.184 (Min)
α Varation of 30° anngle (+/-) 2.25°
P Varation of Pitch (+/-) 0.0006 (Ref) 0.015 (Ref)

* Values are calculated for Length of engagement of 5xPitch. For calculations of different engagement length use the Thread Calculator

* Back to Thread Class Selection


Tap Drill Sizes for #2 - 56 UNC

  • If not specified, assume a thread depth of 75%.
  • You can learn more about thread depth in tapping here.
  • To get the tap drill size in other depths, use our Tap Drill Size Calculator .
Thread Depth Tap Drill Size (Inch) Tap Drill Size (mm)
55% 0.073 1.86
60% 0.072 1.83
65% 0.071 1.80
70% 0.070 1.77
75% 0.069 1.74
80% 0.067 1.71
85% 0.066 1.68

Over Wire Measurements for #2 - 56 UNC


* OverWire is a measuring method to obatin the pitch diameter of threads. It is mostly used when a manufacturer does not have a Go/Nogo gauge for a thread. You can learn more about it here

Inch mm
Permissible Wire Diameter Range 0.009 - 0.0181 0.23 - 0.459
Ideal Wire Diameter 0.0103 0.262
Possible Wires
From Standard Sets
* 0.0103
* 0.0116
* 0.012
* 0.0131
* 0.0144
* 0.016
* 0.018
* 0.231
* 0.26
* 0.289
* 0.346
* 0.404
* 0.433

Once you know your wire diameter, you need to find out what is the premissable Measurement for your pitch diameter (Depending on the class). Use our Over Wire Calculator to find out!


CNC Gcode Program for Turning of #2 - 56 UNC

The below sample Gcode is configured for:

  • Fanuc Controller
  • External RH Thread
  • Right hand tool, machining towards the chuck
  • Flank Infeed method with contant volume
  • Flank Infeed method with contant volume
  • Cutting conditions for steel
  • Default number of passes

You can configure all the above parameters and much more in our Thread Turning Gcode Generator


%
O0100
(MACHINING DOCTOR - THREADING CNC PROGRAM)
(CONTROLER - FANUC A)
(THREAD - )
(D=0.086 INCH, P=0.018 INCH, L=0.179 INCH)
(APPLICATION - EXTERNAL TURNING, TOWARDS CHUCK, RH TOOL, RH THREAD)
(FEED - 17 PASSES, FLANK, CONSTANT VOLUME)
(FINISH PASS - 0.0002 INCH)
(WITH CHAMFER -  NO)
G28 U0
G28 U0
T0100
G99 G97 S5000 M03
G00 Z5.1
G00 X4.2 M08
G76 P010060 Q5 R0
G76 X2 Z-5 P278 Q66 F0 R
G28 U0
G28 U0
M09
M30
(PLEASE NOTE THIS GCODE HAS NOT BEEN TESTED ON YOUR MACHINE AND SETUP. WE CANNOT GUARANTEE ITS ACCURACY OR COMPATIBILITY. NOTE THAT YOU ARE USING IT AT YOUR OWN RISK, AND WE SHALL NOT BE HELD LIABLE FOR ANY DAMAGES OR LOSSES ARISING FROM THE USE OF THIS PROGRAM.)
%

CNC Gcode Program for Thread Milling of #2 - 56 UNC

The below sample Gcode is configured for:

  • Fanuc Controller
  • Internal RH Thread
  • Climb Milling
  • Cutter diameter: 70% of the thread diameter
  • Single tooth Thread Mill cutter
  • Cutting conditions for steel
  • One radial pass

You can configure all the above parameters and much more in our Thread Milling Gcode Generator


%
O0101
(WWW.MACHININGDOCTOR.COM - THREADMILLING PROGRAM)
(CONTROLER - FANUC)
(THREAD - MAJOR DIAM.=0.086 INCH, PITCH=0.017857142857143 INCH, LENGTH=0.17857142857143 INCH)
(APPLICATION - INTERNAL, RH THREAD, CLIMB MILLING)
(CUTTER DIAM=0.043 [SINGLE TOOTH])
(CUTTER COMPENSATION D=0 - TOOLPATH FOR TOOL CENTER)
N1 M06 T1
G54
G90 G40 G17 G94 G21
G00 X0 Y0 S10000 M03
G43 H1 Z25.4 M08
(M-CODE "THROUGH COOLANT ON")
(PASS 1 / 1)
G90 G01 Z-4.5924 F2032
G91 G01 G41 D1 X0.2731 Y-0.2731 F1524
G03 X0.2731 Y0.2731 Z0.0567 I0 J0.2731 F381
G03 Z0.4536 I-0.5461 J0 F762
G03 Z0.4536 I-0.5461 J0
G03 Z0.4536 I-0.5461 J0
G03 Z0.4536 I-0.5461 J0
G03 Z0.4536 I-0.5461 J0
G03 Z0.4536 I-0.5461 J0
G03 Z0.4536 I-0.5461 J0
G03 Z0.4536 I-0.5461 J0
G03 Z0.4536 I-0.5461 J0
G03 Z0.4536 I-0.5461 J0
G03 X-0.2731 Y0.2731 Z0.0567 I-0.2731 J0
G01 G40 X-0.2731 Y-0.2731 F2032
G90 G00 Z25.4
M30
(PLEASE NOTE THIS GCODE HAS NOT BEEN TESTED ON YOUR MACHINE AND SETUP. WE CANNOT GUARANTEE ITS ACCURACY OR COMPATIBILITY. NOTE THAT YOU ARE USING IT AT YOUR OWN RISK, AND WE SHALL NOT BE HELD LIABLE FOR ANY DAMAGES OR LOSSES ARISING FROM THE USE OF THIS PROGRAM.)
%

Our Top Picks

Scroll to Top