ACME Thread data sheet

1.125-5 ACME - Basic Thread Dimensions

Property Inch mm
Major Diameter (D) 1.125 28.575
Pitch (TPI) (P) 5 5
Pitch (Distance) (P) 0.2 5.08
Pitch Diameter (D2) 1.025 26.035
Minor Diameter (D1) 0.925 23.495
Thread Height (h) 0.1 2.54
Flat Width (F) 0.0741 1.882
Profile V Angle (2 X α) 29° 29°
Lead Angle (λ) 3.554° 3.554°
Tap Drill Size (Dt) 0.925 23.495
Thread Family Leadscrew Inch Thread (ACME)
Relevant Standards ASME B1.5

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

Table of Content


1.125-5 ACME Possible Thread Classes

The data listed below is valid only for Single Start Threads and engagement lengthsup to 2.25 For Multiple Starts and large LE's use our ACME Thread Calculator 

External Threads

Choose tolerance class

2G, 3G, 4G, 2C, 3C, 4C

Acme External Thread - Tolerance sketch

Internal Threads

_e("Choose tolerance class","md_acme");

2G, 3G, 4G, 2C, 3C, 4C

ACME Internal Thread - Tolerance sketch

1 1/8 - 5 ACME 2G (External)

* Permisable values forthread Class 2G

# Description Value (Inch) Value (mm)
d Major Diameter 1.115 - 1.125 28.321 - 28.575
d2 Pitch Diameter 0.9967 - 1.0165 25.316 - 25.819
d1 Minor Diameter 0.8753 - 0.905 22.233 - 22.987
P Varation of Pitch (+/-) 0.0009 0.023
α Varation of 14.5° anngle (+/-) 0.45°

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1 1/8 - 5 ACME 3G (External)

* Permisable values forthread Class 3G

# Description Value (Inch) Value (mm)
d Major Diameter 1.115 - 1.125 28.321 - 28.575
d2 Pitch Diameter 1.0094 - 1.0186 25.639 - 25.872
d1 Minor Diameter 0.8912 - 0.905 22.636 - 22.987
P Varation of Pitch (+/-) 0.0009 0.023
α Varation of 14.5° anngle (+/-) 0.45°

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1 1/8 - 5 ACME 4G (External)

* Permisable values forthread Class 4G

# Description Value (Inch) Value (mm)
d Major Diameter 1.115 - 1.125 28.321 - 28.575
d2 Pitch Diameter 1.0142 - 1.0208 25.761 - 25.928
d1 Minor Diameter 0.8951 - 0.905 22.736 - 22.987
P Varation of Pitch (+/-) 0.0009 0.023
α Varation of 14.5° anngle (+/-) 0.45°

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1 1/8 - 5 ACME 2C (External)

* Permisable values forthread Class 2C

# Description Value (Inch) Value (mm)
d Major Diameter 1.1213 - 1.125 28.481 - 28.575
d2 Pitch Diameter 0.9967 - 1.0165 25.316 - 25.819
d1 Minor Diameter 0.8753 - 0.905 22.233 - 22.987
P Varation of Pitch (+/-) 0.0009 0.023
α Varation of 14.5° anngle (+/-) 0.45°

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1 1/8 - 5 ACME 3C (External)

* Permisable values forthread Class 3C

# Description Value (Inch) Value (mm)
d Major Diameter 1.1234 - 1.125 28.534 - 28.575
d2 Pitch Diameter 1.0094 - 1.0186 25.639 - 25.872
d1 Minor Diameter 0.8912 - 0.905 22.636 - 22.987
P Varation of Pitch (+/-) 0.0009 0.023
α Varation of 14.5° anngle (+/-) 0.45°

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1 1/8 - 5 ACME 4C (External)

* Permisable values forthread Class 4C

# Description Value (Inch) Value (mm)
d Major Diameter 1.1239 - 1.125 28.547 - 28.575
d2 Pitch Diameter 1.0142 - 1.0208 25.761 - 25.928
d1 Minor Diameter 0.8951 - 0.905 22.736 - 22.987
P Varation of Pitch (+/-) 0.0009 0.023
α Varation of 14.5° anngle (+/-) 0.45°

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1 1/8 - 5 ACME 2G ( Internal)

* Permisable values for thread Class 2G

# Description Value () Value ()
D Major Diameter 1.145 - 1.165 29.083 - 29.591
D2 Pitch Diameter 1.025 - 1.0448 26.035 - 26.538
D1 Minor Diameter 0.925 - 0.935 23.495 - 23.749
P Varation of Pitch (+/-) 0.0009 (Ref) 0.023 (Ref)
α Varation of 14.5° anngle (+/-) 0.45 (Ref) 11.43 (Ref)

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1 1/8 - 5 ACME 3G ( Internal)

* Permisable values for thread Class 3G

# Description Value () Value ()
D Major Diameter 1.145 - 1.165 29.083 - 29.591
D2 Pitch Diameter 1.025 - 1.0342 26.035 - 26.269
D1 Minor Diameter 0.925 - 0.935 23.495 - 23.749
P Varation of Pitch (+/-) 0.0009 (Ref) 0.023 (Ref)
α Varation of 14.5° anngle (+/-) 0.45 (Ref) 11.43 (Ref)

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1 1/8 - 5 ACME 4G ( Internal)

* Permisable values for thread Class 4G

# Description Value () Value ()
D Major Diameter 1.145 - 1.165 29.083 - 29.591
D2 Pitch Diameter 1.025 - 1.0316 26.035 - 26.203
D1 Minor Diameter 0.925 - 0.935 23.495 - 23.749
P Varation of Pitch (+/-) 0.0009 (Ref) 0.023 (Ref)
α Varation of 14.5° anngle (+/-) 0.45 (Ref) 11.43 (Ref)

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1 1/8 - 5 ACME 2C ( Internal)

* Permisable values for thread Class 2C

# Description Value () Value ()
D Major Diameter 1.1261 - 1.1298 28.603 - 28.697
D2 Pitch Diameter 1.025 - 1.0448 26.035 - 26.538
D1 Minor Diameter 0.945 - 0.955 24.003 - 24.257
P Varation of Pitch (+/-) 0.0009 (Ref) 0.023 (Ref)
α Varation of 14.5° anngle (+/-) 0.45 (Ref) 11.43 (Ref)

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1 1/8 - 5 ACME 3C ( Internal)

* Permisable values for thread Class 3C

# Description Value () Value ()
D Major Diameter 1.1261 - 1.1298 28.603 - 28.697
D2 Pitch Diameter 1.025 - 1.0342 26.035 - 26.269
D1 Minor Diameter 0.945 - 0.955 24.003 - 24.257
P Varation of Pitch (+/-) 0.0009 (Ref) 0.023 (Ref)
α Varation of 14.5° anngle (+/-) 0.45 (Ref) 11.43 (Ref)

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1 1/8 - 5 ACME 4C ( Internal)

* Permisable values for thread Class 4C

# Description Value () Value ()
D Major Diameter 1.1261 - 1.1282 28.603 - 28.656
D2 Pitch Diameter 1.025 - 1.0316 26.035 - 26.203
D1 Minor Diameter 0.945 - 0.955 24.003 - 24.257
P Varation of Pitch (+/-) 0.0009 (Ref) 0.023 (Ref)
α Varation of 14.5° anngle (+/-) 0.45 (Ref) 11.43 (Ref)

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Over Wire Measurements for 1.125-5 ACME


* 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 0.09813 - 0.15494 2.4924 - 3.9353
Ideal Wire Diameter 0.10329 2.6236
Possible Wires
From Standard Sets
* 0.10497
* 0.11547
* 0.1283
* 0.14434
* 2.5981
* 2.8868
* 3.1754
* 3.4641

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!


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