Thread data sheet

Basic Thread Dimensions

Property mm Inch
Nominal Diameter 56 2.2047
Pitch (Distance) 5.5 0.2165
Pitch Diameter 52.428 2.0641
Minor Diameter 50.046 1.9703
Thread Height 2.977 0.1172
Addendum 1.786 0.0703
Crest (External)
Root (Internal)		 0.688 0.0271
Tap Drill Size
(75% depth)		 50.64 1.994
Lead Angle
(Single Start)		 1.91°
Thread Family Metric Coarse Pitch (MC)
Relevant Standards ISO 68-1, ISO 9651-1, ISO 965-2, ISO 261,DIN 13
Equivalent InchThread2 1/4 - 4.5 UNC

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

Choose the Threading Data you want to explore

Unified Inch Thread Classes

Tolerance Classes

Thread Milling CNC program

Thread Milling Gcode

Turning Gcode

Over Wire

Unified Inch Thread Classes

Tolerance Classes

Thread Milling Gcode

Turning Gcode

Over Wire

M56Possible Thread Classes

External Threads

4g, 4h, 6e, 6g, 6h, 8e, 8g, 5g4g, 5h4h, 5g6g, 7g6g, 7h6h, 7e6e, 9e8e, 9g8g

Metric ISO External Thread - Tolerance sketch

Internal Threads

4H, 5H, 5G, 6H, 6G, 7H, 7G, 8G

Metric ISO Internal Thread - Tolerance sketch

M56 4g (External)

* Permisable values for thread Class 4g

# Description Value (mm) Value (Inch)
es Allowance 0.075 (Ref) 0.003 (Ref)
d Major Diameter 55.57 - 55.925 2.1878 - 2.2018
d2 Pitch Diameter 52.183 - 52.353 2.0544 - 2.0611
R Root Radius 0.688 (Min) 0.0271 (Min)
C Root Truncation 0.688 - 1.117 0.0271 - 0.044
LE Normal Length of Engagement 28 - 85 1.1024 - 3.3465

* Back to Thread Class Selection

M56 4h (External)

* Permisable values for thread Class 4h

# Description Value (mm) Value (Inch)
es Allowance 0 (Ref) 0 (Ref)
d Major Diameter 55.645 - 56 2.1907 - 2.2047
d2 Pitch Diameter 52.258 - 52.428 2.0574 - 2.0641
R Root Radius 0.688 (Min) 0.0271 (Min)
C Root Truncation 0.688 - 1.117 0.0271 - 0.044
LE Normal Length of Engagement 28 - 85 1.1024 - 3.3465

* Back to Thread Class Selection

M56 6e (External)

* Permisable values for thread Class 6e

# Description Value (mm) Value (Inch)
es Allowance 0.112 (Ref) 0.0044 (Ref)
d Major Diameter 55.328 - 55.888 2.1783 - 2.2003
d2 Pitch Diameter 52.051 - 52.316 2.0493 - 2.0597
R Root Radius 0.688 (Min) 0.0271 (Min)
C Root Truncation 0.688 - 1.201 0.0271 - 0.0473
LE Normal Length of Engagement 28 - 85 1.1024 - 3.3465

* Back to Thread Class Selection

M56 6g (External)

* Permisable values for thread Class 6g

# Description Value (mm) Value (Inch)
es Allowance 0.075 (Ref) 0.003 (Ref)
d Major Diameter 55.365 - 55.925 2.1797 - 2.2018
d2 Pitch Diameter 52.088 - 52.353 2.0507 - 2.0611
R Root Radius 0.688 (Min) 0.0271 (Min)
C Root Truncation 0.688 - 1.201 0.0271 - 0.0473
LE Normal Length of Engagement 28 - 85 1.1024 - 3.3465

* Back to Thread Class Selection

M56 6h (External)

* Permisable values for thread Class 6h

# Description Value (mm) Value (Inch)
es Allowance 0 (Ref) 0 (Ref)
d Major Diameter 55.44 - 56 2.1827 - 2.2047
d2 Pitch Diameter 52.163 - 52.428 2.0537 - 2.0641
R Root Radius 0.688 (Min) 0.0271 (Min)
C Root Truncation 0.688 - 1.201 0.0271 - 0.0473
LE Normal Length of Engagement 28 - 85 1.1024 - 3.3465

* Back to Thread Class Selection

M56 8e (External)

* Permisable values for thread Class 8e

# Description Value (mm) Value (Inch)
es Allowance 0.112 (Ref) 0.0044 (Ref)
d Major Diameter 54.988 - 55.888 2.1649 - 2.2003
d2 Pitch Diameter 51.891 - 52.316 2.043 - 2.0597
R Root Radius 0.688 (Min) 0.0271 (Min)
C Root Truncation 0.688 - 1.324 0.0271 - 0.0521
LE Normal Length of Engagement 28 - 85 1.1024 - 3.3465

* Back to Thread Class Selection

M56 8g (External)

* Permisable values for thread Class 8g

# Description Value (mm) Value (Inch)
es Allowance 0.075 (Ref) 0.003 (Ref)
d Major Diameter 55.025 - 55.925 2.1663 - 2.2018
d2 Pitch Diameter 51.928 - 52.353 2.0444 - 2.0611
R Root Radius 0.688 (Min) 0.0271 (Min)
C Root Truncation 0.688 - 1.324 0.0271 - 0.0521
LE Normal Length of Engagement 28 - 85 1.1024 - 3.3465

* Back to Thread Class Selection

M56 5g4g (External)

* Permisable values for thread Class 5g4g

# Description Value (mm) Value (Inch)
es Allowance 0.075 (Ref) 0.003 (Ref)
d Major Diameter 55.57 - 55.925 2.1878 - 2.2018
d2 Pitch Diameter 52.141 - 52.353 2.0528 - 2.0611
R Root Radius 0.688 (Min) 0.0271 (Min)
C Root Truncation 0.688 - 1.156 0.0271 - 0.0455
LE Normal Length of Engagement 28 - 85 1.1024 - 3.3465

* Back to Thread Class Selection

M56 5h4h (External)

* Permisable values for thread Class 5h4h

# Description Value (mm) Value (Inch)
es Allowance 0 (Ref) 0 (Ref)
d Major Diameter 55.645 - 56 2.1907 - 2.2047
d2 Pitch Diameter 52.216 - 52.428 2.0557 - 2.0641
R Root Radius 0.688 (Min) 0.0271 (Min)
C Root Truncation 0.688 - 1.156 0.0271 - 0.0455
LE Normal Length of Engagement 28 - 85 1.1024 - 3.3465

* Back to Thread Class Selection

M56 5g6g (External)

* Permisable values for thread Class 5g6g

# Description Value (mm) Value (Inch)
es Allowance 0.075 (Ref) 0.003 (Ref)
d Major Diameter 55.365 - 55.925 2.1797 - 2.2018
d2 Pitch Diameter 52.141 - 52.353 2.0528 - 2.0611
R Root Radius 0.688 (Min) 0.0271 (Min)
C Root Truncation 0.688 - 1.156 0.0271 - 0.0455
LE Normal Length of Engagement 28 - 85 1.1024 - 3.3465

* Back to Thread Class Selection

M56 7g6g (External)

* Permisable values for thread Class 7g6g

# Description Value (mm) Value (Inch)
es Allowance 0.075 (Ref) 0.003 (Ref)
d Major Diameter 55.365 - 55.925 2.1797 - 2.2018
d2 Pitch Diameter 52.018 - 52.353 2.048 - 2.0611
R Root Radius 0.688 (Min) 0.0271 (Min)
C Root Truncation 0.688 - 1.257 0.0271 - 0.0495
LE Normal Length of Engagement 28 - 85 1.1024 - 3.3465

* Back to Thread Class Selection

M56 7h6h (External)

* Permisable values for thread Class 7h6h

# Description Value (mm) Value (Inch)
es Allowance 0 (Ref) 0 (Ref)
d Major Diameter 55.44 - 56 2.1827 - 2.2047
d2 Pitch Diameter 52.093 - 52.428 2.0509 - 2.0641
R Root Radius 0.688 (Min) 0.0271 (Min)
C Root Truncation 0.688 - 1.257 0.0271 - 0.0495
LE Normal Length of Engagement 28 - 85 1.1024 - 3.3465

* Back to Thread Class Selection

M56 7e6e (External)

* Permisable values for thread Class 7e6e

# Description Value (mm) Value (Inch)
es Allowance 0.112 (Ref) 0.0044 (Ref)
d Major Diameter 55.328 - 55.888 2.1783 - 2.2003
d2 Pitch Diameter 51.981 - 52.316 2.0465 - 2.0597
R Root Radius 0.688 (Min) 0.0271 (Min)
C Root Truncation 0.688 - 1.257 0.0271 - 0.0495
LE Normal Length of Engagement 28 - 85 1.1024 - 3.3465

* Back to Thread Class Selection

M56 9e8e (External)

* Permisable values for thread Class 9e8e

# Description Value (mm) Value (Inch)
es Allowance 0.112 (Ref) 0.0044 (Ref)
d Major Diameter 54.988 - 55.888 2.1649 - 2.2003
d2 Pitch Diameter 51.786 - 52.316 2.0388 - 2.0597
R Root Radius 0.688 (Min) 0.0271 (Min)
C Root Truncation 0.688 - 1.397 0.0271 - 0.055
LE Normal Length of Engagement 28 - 85 1.1024 - 3.3465

* Back to Thread Class Selection

M56 9g8g (External)

* Permisable values for thread Class 9g8g

# Description Value (mm) Value (Inch)
es Allowance 0.075 (Ref) 0.003 (Ref)
d Major Diameter 55.025 - 55.925 2.1663 - 2.2018
d2 Pitch Diameter 51.823 - 52.353 2.0403 - 2.0611
R Root Radius 0.688 (Min) 0.0271 (Min)
C Root Truncation 0.688 - 1.397 0.0271 - 0.055
LE Normal Length of Engagement 28 - 85 1.1024 - 3.3465

* Back to Thread Class Selection

M56 4H (Internal)

* Permisable values for thread Class 4H

# Description Value (mm) VValue (Inch)
EL Allowance 0 (Ref) 0 (Ref)
D1 Minor Diameter 50.046 - 50.521 1.9703 - 1.989
D2 Pitch Diameter 52.428 - 52.652 2.0641 - 2.0729
D Major Diameter 56 (Min) 2.2047 (Min)
LE Normal Length of Engagement 28 - 85 1.1024 - 3.3465

* Back to Thread Class Selection

M56 5H (Internal)

* Permisable values for thread Class 5H

# Description Value (mm) VValue (Inch)
EL Allowance 0 (Ref) 0 (Ref)
D1 Minor Diameter 50.046 - 50.646 1.9703 - 1.9939
D2 Pitch Diameter 52.428 - 52.708 2.0641 - 2.0751
D Major Diameter 56 (Min) 2.2047 (Min)
LE Normal Length of Engagement 28 - 85 1.1024 - 3.3465

* Back to Thread Class Selection

M56 5G (Internal)

* Permisable values for thread Class 5G

# Description Value (mm) VValue (Inch)
EL Allowance 0.075 (Ref) 0.003 (Ref)
D1 Minor Diameter 50.121 - 50.721 1.9733 - 1.9969
D2 Pitch Diameter 52.503 - 52.783 2.067 - 2.0781
D Major Diameter 56 (Min) 2.2047 (Min)
LE Normal Length of Engagement 28 - 85 1.1024 - 3.3465

* Back to Thread Class Selection

M56 6H (Internal)

* Permisable values for thread Class 6H

# Description Value (mm) VValue (Inch)
EL Allowance 0 (Ref) 0 (Ref)
D1 Minor Diameter 50.046 - 50.796 1.9703 - 1.9998
D2 Pitch Diameter 52.428 - 52.783 2.0641 - 2.0781
D Major Diameter 56 (Min) 2.2047 (Min)
LE Normal Length of Engagement 28 - 85 1.1024 - 3.3465

* Back to Thread Class Selection

M56 6G (Internal)

* Permisable values for thread Class 6G

# Description Value (mm) VValue (Inch)
EL Allowance 0.075 (Ref) 0.003 (Ref)
D1 Minor Diameter 50.121 - 50.871 1.9733 - 2.0028
D2 Pitch Diameter 52.503 - 52.858 2.067 - 2.081
D Major Diameter 56 (Min) 2.2047 (Min)
LE Normal Length of Engagement 28 - 85 1.1024 - 3.3465

* Back to Thread Class Selection

M56 7H (Internal)

* Permisable values for thread Class 7H

# Description Value (mm) VValue (Inch)
EL Allowance 0 (Ref) 0 (Ref)
D1 Minor Diameter 50.046 - 50.996 1.9703 - 2.0077
D2 Pitch Diameter 52.428 - 52.878 2.0641 - 2.0818
D Major Diameter 56 (Min) 2.2047 (Min)
LE Normal Length of Engagement 28 - 85 1.1024 - 3.3465

* Back to Thread Class Selection

M56 7G (Internal)

* Permisable values for thread Class 7G

# Description Value (mm) VValue (Inch)
EL Allowance 0.075 (Ref) 0.003 (Ref)
D1 Minor Diameter 50.121 - 51.071 1.9733 - 2.0107
D2 Pitch Diameter 52.503 - 52.953 2.067 - 2.0848
D Major Diameter 56 (Min) 2.2047 (Min)
LE Normal Length of Engagement 28 - 85 1.1024 - 3.3465

* Back to Thread Class Selection

M56 8G (Internal)

* Permisable values for thread Class 8G

# Description Value (mm) VValue (Inch)
EL Allowance 0.075 (Ref) 0.003 (Ref)
D1 Minor Diameter 50.121 - 51.301 1.9733 - 2.0197
D2 Pitch Diameter 52.503 - 53.063 2.067 - 2.0891
D Major Diameter 56 (Min) 2.2047 (Min)
LE Normal Length of Engagement 28 - 85 1.1024 - 3.3465

* Back to Thread Class Selection

Over Wire Measurements for M56


* 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

mm Inch
Permissible Wire Diameter Range 2.779 - 5.557 0.1094 - 0.2188
Ideal Wire Diameter 3.175 0.125
Possible Wires
From Standard Sets		 * 2.887
* 3.175
* 3.464
* 4.042
* 4.619
* 5.196
 * 0.1155
* 0.1283
* 0.1443
* 0.165
* 0.1777
* 0.1925
* 0.21

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 M56

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=56 MM, P=5.5 MM, L=55 MM)
(APPLICATION - EXTERNAL TURNING, TOWARDS CHUCK, RH TOOL, RH THREAD)
(FEED - 16 PASSES, FLANK, CONSTANT VOLUME)
(FINISH PASS - 0.052 MM)
(WITH CHAMFER -  NO)
G28 U0 W0
T0101 G99 G97 S568 M03
G00 Z10.0
X 66.0 M08
G76 P010060 Q52 R0.052
G76 X49.252 Z-55.0 P3374 Q830 F5.5 R0.00 
G28 U0 W0
M09
M30
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CNC Gcode Program for Thread Milling of M56

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 


%
O101
(WWW.MACHININGDOCTOR.COM - THREADMILLING PROGRAM)
(CONTROLER - FANUC)
(THREAD - D=56 MM, P=5.5 MM, L=55 MM)
(APPLICATION - INTERNAL, RH THREAD, CLIMB MILLING)
(CUTTER - D=28 [SINGLE TOOTH])
N1 M06 T1
G54
G90 G40 G17 G94 G21
G00 X0 Y0 S1137 M03
G43 H1 Z20.0 M08
(M-CODE "THROUGH COOLANT ON")
(PASS 1 / 1)
G90 G01 Z-55.688 F2000
G91 G01 G41 D1 X7.0 Y-7.0 F171
G03 X7.0 Y7.0 Z0.688 I0 J7.0 F43
G03 Z5.5 I-14.0 J0 F85
G03 Z5.5 I-14.0 J0
G03 Z5.5 I-14.0 J0
G03 Z5.5 I-14.0 J0
G03 Z5.5 I-14.0 J0
G03 Z5.5 I-14.0 J0
G03 Z5.5 I-14.0 J0
G03 Z5.5 I-14.0 J0
G03 Z5.5 I-14.0 J0
G03 Z5.5 I-14.0 J0
G03 X-7.0 Y7.0 Z0.688 I-7.0 J0
G01 G40 X-7.0 Y-7.0 F2000
G90 G00 Z20.0
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.)
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