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

Property Inch mm
Nominal Diameter 0.687 17.45
Pitch (TPI)16
Pitch (Distance) 0.0625 1.588
Pitch Diameter 0.6464 16.419
Minor Diameter 0.6126 15.56
Thread Height 0.0338 0.859
Addendum 0.0203 0.516
Crest (External)
Root (Internal)
0.0078 0.198
Tap Drill Size
(75% depth)
0.626 15.9
Lead Angle
(Single Start)
1.76°
Thread Family Unified Constant Pitch 16 TPI (16-UN)
Relevant Standards ASME B1.1-2003
Equivalent Metric ThreadM18 X 1.5

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

Table of Content


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

* Permisable values for thread Class 2A

# Description Value (Inch) Value (mm)
es Allowance 0.0014 (Ref) 0.036 (Ref)
d Major Diameter 0.6762 - 0.6856 17.175 - 17.414
d2 Pitch Diameter 0.6405 - 0.645 16.269 - 16.383
d3 Minor Diameter
(UNR Only)
0.6112 (Ref) 15.524 (Ref)
α Varation of 30° anngle (+/-)
P Varation of pitch (+/-) 0.0013 (Ref) 0.033 (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 - 16 16-UN 3A (External)

* Permisable values for thread Class 3A

# Description Value (Inch) Value (mm)
es Allowance 0 (Ref) 0 (Ref)
d Major Diameter 0.6776 - 0.687 17.211 - 17.45
d2 Pitch Diameter 0.643 - 0.6464 16.332 - 16.419
d3 Minor Diameter
(UNR Only)
0.6126 (Ref) 15.56 (Ref)
α Varation of 30° anngle (+/-)
P Varation of pitch (+/-) 0.001 (Ref) 0.025 (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 - 16 16-UN 2B (Internal)

* Permisable values for thread Class 2B

# Description Value (Inch) Value (mm)
D1 Minor Diameter 0.619 - 0.633 15.723 - 16.078
D2 Pitch Diameter 0.6464 - 0.6523 16.419 - 16.568
D Major Diameter 0.6870 (Min) 17.45 (Min)
α Varation of 30° anngle (+/-)
P Varation of Pitch (+/-) 0.0017 (Ref) 0.043 (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 - 16 16-UN 3B (Internal)

* Permisable values for thread Class 3B

# Description Value (Inch) Value (mm)
D1 Minor Diameter 0.6193 - 0.6279 15.73 - 15.949
D2 Pitch Diameter 0.6464 - 0.6508 16.419 - 16.53
D Major Diameter 0.6870 (Min) 17.45 (Min)
α Varation of 30° anngle (+/-)
P Varation of Pitch (+/-) 0.0013 (Ref) 0.033 (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 - 16 16-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% 0.642 16.31
60% 0.638 16.21
65% 0.634 16.11
70% 0.630 16.01
75% 0.626 15.90
80% 0.622 15.80
85% 0.618 15.70

Over Wire Measurements for 11/16 - 16 16-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 0.0316 - 0.0631 0.802 - 1.604
Ideal Wire Diameter 0.0361 0.917
Possible Wires
From Standard Sets
* 0.866
* 1.01
* 1.155
* 1.443

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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