13/16 - 32 32-UN - Basic Thread Dimensions

Property Inch mm
Nominal Diameter 0.812 20.625
Pitch (TPI)32
Pitch (Distance) 0.0313 0.795
Pitch Diameter 0.7917 20.109
Minor Diameter 0.7748 19.68
Thread Height 0.0169 0.429
Addendum 0.0101 0.257
Crest (External)
Root (Internal)
0.0039 0.099
Tap Drill Size
(75% depth)
0.781 19.85
Lead Angle
(Single Start)
0.72°
Thread Family Unified Constant Pitch 32 TPI (32-UN)
Relevant Standards ASME B1.1-2003
Equivalent Metric ThreadM20 X 1

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

Table of Content


13/16 - 32 32-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

13/16 - 32 32-UN 2A (External)

* Permisable values for thread Class 2A

# Description Value (Inch) Value (mm)
es Allowance 0.001 (Ref) 0.025 (Ref)
d Major Diameter 0.805 - 0.811 20.447 - 20.599
d2 Pitch Diameter 0.7872 - 0.7907 19.995 - 20.084
d3 Minor Diameter
(UNR Only)
0.7737 (Ref) 19.652 (Ref)
α Varation of 30° anngle (+/-) 1.5°
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


13/16 - 32 32-UN 3A (External)

* Permisable values for thread Class 3A

# Description Value (Inch) Value (mm)
es Allowance 0 (Ref) 0 (Ref)
d Major Diameter 0.806 - 0.812 20.472 - 20.625
d2 Pitch Diameter 0.7891 - 0.7917 20.043 - 20.109
d3 Minor Diameter
(UNR Only)
0.7748 (Ref) 19.68 (Ref)
α Varation of 30° anngle (+/-) 1.5°
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


13/16 - 32 32-UN 2B (Internal)

* Permisable values for thread Class 2B

# Description Value (Inch) Value (mm)
D1 Minor Diameter 0.778 - 0.786 19.761 - 19.964
D2 Pitch Diameter 0.7917 - 0.7962 20.109 - 20.223
D Major Diameter 0.8120 (Min) 20.625 (Min)
α Varation of 30° anngle (+/-) 1.5°
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


13/16 - 32 32-UN 3B (Internal)

* Permisable values for thread Class 3B

# Description Value (Inch) Value (mm)
D1 Minor Diameter 0.7782 - 0.7839 19.766 - 19.911
D2 Pitch Diameter 0.7917 - 0.7951 20.109 - 20.196
D Major Diameter 0.8120 (Min) 20.625 (Min)
α Varation of 30° anngle (+/-) 1.5°
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


Tap Drill Sizes for 13/16 - 32 32-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% 0.790 20.06
60% 0.788 20.01
65% 0.786 19.95
70% 0.784 19.90
75% 0.782 19.85
80% 0.780 19.80
85% 0.777 19.75

Over Wire Measurements for 13/16 - 32 32-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 0.0158 - 0.0316 0.402 - 0.803
Ideal Wire Diameter 0.0181 0.459
Possible Wires
From Standard Sets
* 0.016
* 0.018
* 0.0193
* 0.0206
* 0.0214
* 0.0222
* 0.0241
* 0.0262
* 0.0289
* 0.404
* 0.433
* 0.462
* 0.52
* 0.577
* 0.722

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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