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ACME Thread Plug Gages

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ACME Thread Plug Gages

FEATURES:
  • Gages an internal threaded product
  • 3 classes of fit – 2G, 3G, 4G
  • Centralizing ACME threads classes of fit:: 2C, 3C, 4C
  • ACME thread plug gages compliant to ASME B1.5-1997
  • ACME thread plug gage lengths and blank standards compliant to ASME B47.1


External ACME Thread Size Chart



Internal ACME Thread Size Chart


Size Class TPI PD Member Item # Price
.2500-16 2G16.2188"/.2293"GO / NOGOACMETPG1Call
SETACMETPGS1Call
3G16.2188"/.2237"GO / NOGOACMETPG2Call
SETACMETPGS2Call
4G16 .2188"/.2223"GO / NOGOACMETPG3Call
SETACMETPGS3Call
.3125-14 2G14.2768"/.2882"GO / NOGOACMETPG4Call
SETACMETPGS4Call
3G14.2768"/.2821"GO / NOGOACMETPG5Call
SETACMETPGS5Call
4G14.2768"/.2806"GO / NOGOACMETPG6Call
SETACMETPGS6Call
.3750-12 2G12.3333"/.3456"GO / NOGOACMETPG7Call
SETACMETPGS7Call
3G12.3333"/.3391"GO / NOGOACMETPG8Call
SETACMETPGS8Call
4G12.3333"/.3374"GO / NOGOACMETPG9Call
SETACMETPGS9Call
.4375-12 2G12.3958"/.4084"GO / NOGOACMETPG10Call
SETACMETPGS10Call
3G12.3958"/.4017"GO / NOGOACMETPG11Call
SETACMETPGS11Call
4G12.3958"/.4000"GO / NOGOACMETPG12Call
SETACMETPGS12Call
.5000-10 2G10.4500"/.4637"GO / NOGOACMETPG13Call
SETACMETPGS13Call
3G10.4500"/.4564"GO / NOGOACMETPG14Call
SETACMETPGS14Call
4G10.4500"/.4546"GO / NOGOACMETPG15Call
SETACMETPGS15Call
.6250-8 2G8.5625"/.5779"GO / NOGOACMETPG16Call
SETACMETPGS16Call
3G8.5625"/.5697"GO / NOGOACMETPG17Call
SETACMETPGS17Call
4G8.5625"/.5676"GO / NOGOACMETPG18Call
SETACMETPGS18Call
.7500-6 2G6.6667"/.6841"GO / NOGOACMETPG19Call
SETACMETPGS19Call
3G6.6667".6748"GO / NOGOACMETPG20Call
SETACMETPGS20Call
4G6.6667"/.6725"GO / NOGOACMETPG21Call
SETACMETPGS21Call
.8750-6 2G6.7917"/.8096"GO / NOGOACMETPG22Call
SETACMETPGS22Call
3G6.7917"/.8000"GO / NOGOACMETPG23Call
SETACMETPGS23Call
4G6.7917"/.7977"GO / NOGOACMETPG24Call
SETACMETPGS24Call
1.0000-5 2G5.9000"/.9194"GO / NOGOACMETPG25Call
SETACMETPGS25Call
3G5.9000"/.9091"GO / NOGOACMETPG26Call
SETACMETPGS26Call
4G5.9000"/9065"GO / NOGOACMETPG27Call
SETACMETPGS27Call
1.1250-5 2G51.0250"/1.0448"GO / NOGOACMETPG28Call
SETACMETPGS28Call
3G51.0250"/1.0342"GO / NOGOACMETPG29Call
SETACMETPGS29Call
4G51.0250"/1.0316"GO / NOGOACMETPG30Call
SETACMETPGS30Call
1.2500-5 2G51.1500"/1.1701"GO / NOGOACMETPG31Call
SETACMETPGS31Call
3G51.1500"/1.1594"GO / NOGOACMETPG32Call
SETACMETPGS32Call
4G51.1500"/1.1567"GO / NOGOACMETPG33Call
SETACMETPGS33Call
1.3750-4 2G41.2500"/1.2720"GO / NOGOACMETPG34Call
SETACMETPGS34Call
3G41.2500"/1.2603"GO / NOGOACMETPG35Call
SETACMETPGS35Call
4G41.2500"/1.2573"GO / NOGOACMETPG36Call
SETACMETPGS36Call
1.5000-4 2G41.3750"/1.3973"GO / NOGOACMETPG37Call
SETACMETPGS37Call
3G41.3750"/1.3854"GO / NOGOACMETPG38Call
SETACMETPGS38Call
4G41.3750"/1.3824"GO / NOGOACMETPG39Call
SETACMETPGS39Call
1.7500-4 2G41.6250"/1.6479"GO / NOGOACMETPG40Call
SETACMETPGS40Call
3G41.6250"/1.6357"GO / NOGOACMETPG41Call
SETACMETPGS41Call
4G41.6250"/1.6326"GO / NOGOACMETPG42Call
SETACMETPGS42Call
2.000-4 2G41.8750"/1.8985"GO / NOGOACMETPG43Call
SETACMETPGS43Call
3G41.8750"/1.8860"GO / NOGOACMETPG44Call
SETACMETPGS44Call
4G41.8750"/1.8828"GO / NOGOACMETPG45Call
SETACMETPGS45Call
2.2500-3 2G32.0833"/2.1096"GO / NOGOACMETPG46Call
SETACMETPGS46Call
3G32.0833"/2.0956"GO / NOGOACMETPG47Call
SETACMETPGS47Call
4G32.0833"/2.0921"GO / NOGOACMETPG48Call
SETACMETPGS48Call
2.500-3 2G32.3333"/2.3601"GO / NOGOACMETPG49Call
SETACMETPGS49Call
3G32.3333"/2.3458"GO / NOGOACMETPG50Call
SETACMETPGS50Call
4G32.3333"/2.3422"GO / NOGOACMETPG51Call
SETACMETPGS51Call
2.7500-3 2G32.5833"/2.6106"GO / NOGOACMETPG52Call
SETACMETPGS52Call
3G32.5833"/2.5960"GO / NOGOACMETPG53Call
SETACMETPGS53Call
4G32.5833"/2.5924"GO / NOGOACMETPG54Call
SETACMETPGS54Call
3.0000-2 2G22.7500"/2.7816"GO / NOGOACMETPG55Call
SETACMETPGS55Call
3G22.7500"/2.7647"GO / NOGOACMETPG56Call
SETACMETPGS56Call
4G22.7500"/2.7605"GO / NOGOACMETPG57Call
SETACMETPGS57Call
3.5000-2 2G23.2500"/3.2824"GO / NOGOACMETPG58Call
SETACMETPGS58Call
3G23.2500"/3.2651"GO / NOGOACMETPG59Call
SETACMETPGS59Call
4G23.2500"/3.2608"GO / NOGOACMETPG60Call
SETACMETPGS60Call
4.0000-2 2G23.7500"/3.7832"GO / NOGOACMETPG61Call
SETACMETPGS61Call
3G23.7500"/3.7655"GO / NOGOACMETPG62Call
SETACMETPGS62Call
4G23.7500"/3.7611"GO / NOGOACMETPG63Call
SETACMETPGS63Call
4.5000-2 2G24.2500"/4.2839"GO / NOGOACMETPG64Call
SETACMETPGS64Call
3G24.2500"/4.2658"GO / NOGOACMETPG65Call
SETACMETPGS65Call
4G24.2500"/4.2613"GO / NOGOACMETPG66Call
SETACMETPGS66Call
5.0000-2 2G24.7500"/4.7846"GO / NOGOACMETPG67Call
SETACMETPGS67Call
3G24.7500"/4.7662"GO / NOGOACMETPG68Call
SETACMETPGS68Call
4G24.7500"/4.7615"GO / NOGOACMETPG69Call
SETACMETPGS69Call


Acme Thread Plug Gages

Product Description:

WESTport Gage provides a complete line of standard and special General Purpose ACME GO/NO GO Thread Plug Gages in compliance with ASME B1.5 - 1997. Acme Thread Plug Gages are used to gage an internal threaded product.. The ACME thread list of diameters listed here and their associated pitches are recommended as preferred. They have been specifically selected to meet requirements with the least number of items. In doing so this keeps the inventory of gages and tooling to a minimum in an effort to reduce costs.

There are three classes of fit for ACME General Purpose thread gages; 2G, 3G and 4G. Centralizing ACME threads have classes of fit which are 2C, 3C and 4C. ACME threads feature a 29 degree angle of thread which is the angle between the sides of the thread measured in an axial plane. ACME Thread Plug Gage lengths and blank standards are compliant to ASME B47.1 Centralizing ACME thread gages, Multiple start ACME thread gages and any special requirements will be priced on request.

Definition and Uses

Screw threads fall into a few different categories: normal, square and ACME. These thread types different in shape, strength, and usage. You are probably familiar with normal screw threads like the ones below.


Fig. 1 Normal thread examples

Normal threads are used in thousands of different applications and products. You can tell from the image that the thread is triangular, thin, and sharp. Unlike normal threads, ACME and square threads are blunt and used in very specific ways.

ACME threads are trapezoidal, which means that they are not sharp like a normal thread, but the base of the thread is slightly wider than the top, unlike a square thread.


Fig. 2 ACME thread example


Fig. 3 Square thread example

ACME thread form is commonly used for applications that involve high accuracy or very large loads. They are often used for lead screws (which are screws that convert turning motion into linear motion) and in lathes and vises, but are also found in many other applications and products like jacks and aircraft flaps. The square thread form was originally used for these applications, but the trapezoidal or ACME form has mostly replaced it because it is easier to manufacture, and it is stronger than the square form.

Types of ACME Threads

ACME thread forms have a thread angle of 29°, and the similar trapezoidal metric thread form has a thread angle of 30°. Both are commonly used, but the ACME thread is the most prolific throughout the world, even in countries that use the metric system. ACME threads and gages come in two main types with the respective classes of fit.

  • General purpose ACMEs are used in a wide variety of machines. They have a clearance on all diameters, which allows for free movement. General purpose ACMEs fall into three classes of fit: 2G, 3G and 4G. (Class of fit refers to the allowable range of tolerance, or amount of interference, where 2G has the loosest fit and 4G the tightest.) They are used in applications that do not require strictly holding major diameter.
  • Centralizing ACMEs differ from the general purpose only in the clearance of the major diameter. Centralizing ACMEs have limited clearance at the major diameter, which keeps alignment and prevents wedging, binding, and crossing threads. Five classes of fit exist for centralizing ACMEs: 2C, 3C, 4C, 5C and 6C. Classes 2C, 3C and 4C are most common.

ACME Thread Gages

Because ACME threads are often used for precise manufacturing machines, it is vital to routinely inspect and calibrate the threads. An Acme thread ring gage is used to check tolerances; it will feature a GO and a NO GO member. If the threads are within tolerance, the GO member should completely screw on, and the NO GO member should not. WESTport Corporation offers ACME GO/NO GO thread ring gages for external threads in classes 2G, 3G, 4G, 2C, 3C, and 4C. These top-quality gages comply with ASME B1.5-1997. Acme thread set plug gages are used to insure that the thread ring gage is calibrated properly and are compliant to ASME B1.5-1997.

Written by K. Hansen, Edited by Robert Forbes – WESTport Corporation – February 23, 2015


WESTport Manufactured Products. 24th Anniversary Servicing Industry Worldwide (1989-2013)