11/16 - 12 12-UN - Basic Thread Dimensions

Property Inch mm
Nominal Diameter 0.687 17.45
Pitch (TPI)12
Pitch (Distance) 0.0833 2.116
Pitch Diameter 0.6329 16.076
Minor Diameter 0.5878 14.93
Thread Height 0.0451 1.146
Addendum 0.0271 0.688
Crest (External)
Root (Internal)
0.0104 0.264
Tap Drill Size
(75% depth)
0.606 15.39
Lead Angle
(Single Start)
2.4°
Thread Family Unified Constant Pitch 6 TPI (12-UN)
Relevant Standards ASME B1.1-2003
Equivalent Metric ThreadM18 X 2

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

Table of Content


11/16 - 12 12-UN Possible Thread Classes

External Threads

Choose tolerance class: 2A, 3A

Metric ISO External Thread - Tolerance sketch

Internal Threads

Choose tolerance class: 2B, 3B

Metric ISO Internal Thread - Tolerance sketch

11/16 - 12 12-UN 2A (External)

* Permisable values for thread Class 2A

# Description Value (Inch) Value (mm)
es Allowance 0.0015 (Ref) 0.038 (Ref)
d Major Diameter 0.6741 - 0.6855 17.122 - 17.412
d2 Pitch Diameter 0.6262 - 0.6314 15.905 - 16.038
d3 Minor Diameter
(UNR Only)
0.5862 (Ref) 14.889 (Ref)
α Varation of 30° anngle (+/-) 0.9167°
P Varation of pitch (+/-) 0.0015 (Ref) 0.038 (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


11/16 - 12 12-UN 3A (External)

* Permisable values for thread Class 3A

# Description Value (Inch) Value (mm)
es Allowance 0 (Ref) 0 (Ref)
d Major Diameter 0.6756 - 0.687 17.16 - 17.45
d2 Pitch Diameter 0.629 - 0.6329 15.977 - 16.076
d3 Minor Diameter
(UNR Only)
0.5878 (Ref) 14.93 (Ref)
α Varation of 30° anngle (+/-) 0.9167°
P Varation of pitch (+/-) 0.0011 (Ref) 0.028 (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


11/16 - 12 12-UN 2B (Internal)

* Permisable values for thread Class 2B

# Description Value (Inch) Value (mm)
D1 Minor Diameter 0.597 - 0.615 15.164 - 15.621
D2 Pitch Diameter 0.6329 - 0.6396 16.076 - 16.246
D Major Diameter 0.6870 (Min) 17.45 (Min)
α Varation of 30° anngle (+/-) 0.9167°
P Varation of Pitch (+/-) 0.0019 (Ref) 0.048 (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


11/16 - 12 12-UN 3B (Internal)

* Permisable values for thread Class 3B

# Description Value (Inch) Value (mm)
D1 Minor Diameter 0.5968 - 0.608 15.159 - 15.443
D2 Pitch Diameter 0.6329 - 0.6379 16.076 - 16.203
D Major Diameter 0.6870 (Min) 17.45 (Min)
α Varation of 30° anngle (+/-) 0.9167°
P Varation of Pitch (+/-) 0.0015 (Ref) 0.038 (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 11/16 - 12 12-UN

  • 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% 0.627 15.94
60% 0.622 15.80
65% 0.617 15.66
70% 0.611 15.52
75% 0.606 15.39
80% 0.600 15.25
85% 0.595 15.11

Over Wire Measurements for 11/16 - 12 12-UN


* 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 0.0421 - 0.0842 1.069 - 2.138
Ideal Wire Diameter 0.0481 1.222
Possible Wires
From Standard Sets
* 0.0642
* 0.0722
* 0.077
* 0.0825
* 1.155
* 1.443
* 1.732
* 2.021

Once you knoe 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!


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