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Gages

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
SIZE CLASS TPI PD MEMBER ITEM# PRICE
5.0000-2 4G 2 4.7500"/4.7615" SET ACMETPGS69 call
5.0000-2 4G 2 4.7500"/4.7615" GO/NOGO ACMETPG69 call
5.0000-2 3G 2 4.7500"/4.7662" SET ACMETPGS68 call
5.0000-2 3G 2 4.7500"/4.7662" GO/NOGO ACMETPG68 call
5.0000-2 2G 2 4.7500"/4.7846" SET ACMETPGS67 call
5.0000-2 2G 2 4.7500"/4.7846" GO/NOGO ACMETPG67 call
4.5000-2 4G 2 4.2500"/4.2613" SET ACMETPGS66 call
4.5000-2 4G 2 4.2500"/4.2613" GO/NOGO ACMETPG66 call
4.5000-2 3G 2 4.2500"/4.2658" SET ACMETPGS65 call
4.5000-2 3G 2 4.2500"/4.2658" GO/NOGO ACMETPG65 call
4.5000-2 2G 2 4.2500"/4.2839" SET ACMETPGS64 call
4.5000-2 2G 2 4.2500"/4.2839" GO/NOGO ACMETPG64 call
4.0000-2 4G 2 3.7500"/3.7611" SET ACMETPGS63 call
4.0000-2 4G 2 3.7500"/3.7611" GO/NOGO ACMETPG63 call
4.0000-2 3G 2 3.7500"/3.7655" SET ACMETPGS62 call
4.0000-2 3G 2 3.7500"/3.7655" GO/NOGO ACMETPG62 call
4.0000-2 2G 2 3.7500"/3.7832" SET ACMETPGS61 call
4.0000-2 2G 2 3.7500"/3.7832" GO/NOGO ACMETPG61 call
3.5000-2 4G 2 3.2500"/3.2608" SET ACMETPGS60 call
3.5000-2 4G 2 3.2500"/3.2608" GO/NOGO ACMETPG60 call
3.5000-2 3G 2 3.2500"/3.2651" SET ACMETPGS59 call
3.5000-2 3G 2 3.2500"/3.2651" GO/NOGO ACMETPG59 call
3.5000-2 2G 2 3.2500"/3.2824" SET ACMETPGS58 call
3.5000-2 2G 2 3.2500"/3.2824" GO/NOGO ACMETPG58 call
3.0000-2 4G 2 2.7500"/2.7605" SET ACMETPGS57 call
3.0000-2 4G 2 2.7500"/2.7605" GO/NOGO ACMETPG57 call
3.0000-2 3G 2 2.7500"/2.7647" SET ACMETPGS56 call
3.0000-2 3G 2 2.7500"/2.7647" GO/NOGO ACMETPG56 call
3.0000-2 2G 2 2.7500"/2.7816" SET ACMETPGS55 call
3.0000-2 2G 2 2.7500"/2.7816" GO/NOGO ACMETPG55 call
2.7500-3 4G 3 2.5833"/2.5924" SET ACMETPGS54 call
2.7500-3 4G 3 2.5833"/2.5924" GO/NOGO ACMETPG54 call
2.7500-3 3G 3 2.5833"/2.5960" SET ACMETPGS53 call
2.7500-3 3G 3 2.5833"/2.5960" GO/NOGO ACMETPG53 call
2.7500-3 2G 3 2.5833"/2.6106" SET ACMETPGS52 call
2.7500-3 2G 3 2.5833"/2.6106" GO/NOGO ACMETPG52 call
2.500-3 4G 3 2.3333"/2.3422" SET ACMETPGS51 call
2.500-3 4G 3 2.3333"/2.3422" GO/NOGO ACMETPG51 call
2.500-3 3G 3 2.3333"/2.3458" SET ACMETPGS50 call
2.500-3 3G 3 2.3333"/2.3458" GO/NOGO ACMETPG50 call
2.500-3 2G 3 2.3333"/2.3601" SET ACMETPGS49 call
2.500-3 2G 3 2.3333"/2.3601" GO/NOGO ACMETPG49 call
2.2500-3 4G 3 2.0833"/2.0921" SET ACMETPGS48 call
2.2500-3 4G 3 2.0833"/2.0921" GO/NOGO ACMETPG48 call
2.2500-3 3G 3 2.0833"/2.0956" SET ACMETPGS47 call
2.2500-3 3G 3 2.0833"/2.0956" GO/NOGO ACMETPG47 call
2.2500-3 2G 3 2.0833"/2.1096" SET ACMETPGS46 call
2.2500-3 2G 3 2.0833"/2.1096" GO/NOGO ACMETPG46 call
2.000-4 4G 4 1.8750"/1.8828" SET ACMETPGS45 call
2.000-4 4G 4 1.8750"/1.8828" GO/NOGO ACMETPG45 call
2.000-4 3G 4 1.8750"/1.8860" SET ACMETPGS44 call
2.000-4 3G 4 1.8750"/1.8860" GO/NOGO ACMETPG44 call
2.000-4 2G 4 1.8750"/1.8985" SET ACMETPGS43 call
2.000-4 2G 4 1.8750"/1.8985" GO/NOGO ACMETPG43 call
1.7500-4 4G 4 1.6250"/1.6326" SET ACMETPGS42 call
1.7500-4 4G 4 1.6250"/1.6326" GO/NOGO ACMETPG42 call
1.7500-4 3G 4 1.6250"/1.6357" SET ACMETPGS41 call
1.7500-4 3G 4 1.6250"/1.6357" GO/NOGO ACMETPG41 call
1.7500-4 2G 4 1.6250"/1.6479" SET ACMETPGS40 call
1.7500-4 2G 4 1.6250"/1.6479" GO/NOGO ACMETPG40 call
1.5000-4 4G 4 1.3750"/1.3824" SET ACMETPGS39 call
1.5000-4 4G 4 1.3750"/1.3824" GO/NOGO ACMETPG39 call
1.5000-4 3G 4 1.3750"/1.3854" SET ACMETPGS38 call
1.5000-4 3G 4 1.3750"/1.3854" GO/NOGO ACMETPG38 call
1.5000-4 2G 4 1.3750"/1.3973" SET ACMETPGS37 call
1.5000-4 2G 4 1.3750"/1.3973" GO/NOGO ACMETPG37 call
1.3750-4 4G 4 1.2500"/1.2573" SET ACMETPGS36 call
1.3750-4 4G 4 1.2500"/1.2573" GO/NOGO ACMETPG36 call
1.3750-4 3G 4 1.2500"/1.2603" SET ACMETPGS35 call
1.3750-4 3G 4 1.2500"/1.2603" GO/NOGO ACMETPG35 call
1.3750-4 2G 4 1.2500"/1.2720" SET ACMETPGS34 call
1.3750-4 2G 4 1.2500"/1.2720" GO/NOGO ACMETPG34 call
1.2500-5 4G 5 1.1500"/1.1567" SET ACMETPGS33 call
1.2500-5 4G 5 1.1500"/1.1567" GO/NOGO ACMETPG33 call
1.2500-5 3G 5 1.1500"/1.1594" SET ACMETPGS32 call
1.2500-5 3G 5 1.1500"/1.1594" GO/NOGO ACMETPG32 call
1.2500-5 2G 5 1.1500"/1.1701" SET ACMETPGS31 call
1.2500-5 2G 5 1.1500"/1.1701" GO/NOGO ACMETPG31 call
1.1250-5 4G 5 1.0250"/1.0316" SET ACMETPGS30 call
1.1250-5 4G 5 1.0250"/1.0316" GO/NOGO ACMETPG30 call
1.1250-5 3G 5 1.0250"/1.0342" SET ACMETPGS29 call
1.1250-5 3G 5 1.0250"/1.0342" GO/NOGO ACMETPG29 call
1.1250-5 2G 5 1.0250"/1.0448" SET ACMETPGS28 call
1.1250-5 2G 5 1.0250"/1.0448" GO/NOGO ACMETPG28 call
1.0000-5 4G 5 .9000"/9065" SET ACMETPGS27 call
1.0000-5 4G 5 .9000"/9065" GO/NOGO ACMETPG27 call
1.0000-5 3G 5 .9000"/.9091" SET ACMETPGS26 call
1.0000-5 3G 5 .9000"/.9091" GO/NOGO ACMETPG26 call
1.0000-5 2G 5 .9000"/.9194" SET ACMETPGS25 call
1.0000-5 2G 5 .9000"/.9194" GO/NOGO ACMETPG25 call
.8750-6 4G 6 .7917"/.7977" SET ACMETPGS24 call
.8750-6 4G 6 .7917"/.7977" GO/NOGO ACMETPG24 call
.8750-6 3G 6 .7917"/.8000" SET ACMETPGS23 call
.8750-6 3G 6 .7917"/.8000" GO/NOGO ACMETPG23 call
.8750-6 2G 6 .7917"/.8096" SET ACMETPGS22 call
.8750-6 2G 6 .7917"/.8096" GO/NOGO ACMETPG22 call
.7500-6 4G 6 .6667"/.6725" SET ACMETPGS21 call
.7500-6 4G 6 .6667"/.6725" GO/NOGO ACMETPG21 call
.7500-6 3G 6 .6667".6748" SET ACMETPGS20 call
.7500-6 3G 6 .6667".6748" GO/NOGO ACMETPG20 call
.7500-6 2G 6 .6667"/.6841" SET ACMETPGS19 call
.7500-6 2G 6 .6667"/.6841" GO/NOGO ACMETPG19 call
.6250-8 4G 8 .5625"/.5676" SET ACMETPGS18 call
.6250-8 4G 8 .5625"/.5676" GO/NOGO ACMETPG18 call
.6250-8 3G 8 .5625"/.5697" SET ACMETPGS17 call
.6250-8 3G 8 .5625"/.5697" GO/NOGO ACMETPG17 call
.6250-8 2G 8 .5625"/.5779" SET ACMETPGS16 call
.6250-8 2G 8 .5625"/.5779" GO/NOGO ACMETPG16 call
.5000-10 4G 10 .4500"/.4546" SET ACMETPGS15 call
.5000-10 4G 10 .4500"/.4546" GO/NOGO ACMETPG15 call
.5000-10 3G 10 .4500"/.4564" SET ACMETPGS14 call
.5000-10 3G 10 .4500"/.4564" GO/NOGO ACMETPG14 call
.5000-10 2G 10 .4500"/.4637" SET ACMETPGS13 call
.5000-10 2G 10 .4500"/.4637" GO/NOGO ACMETPG13 call
.4375-12 4G 12 .3958"/.4000" SET ACMETPGS12 call
.4375-12 4G 12 .3958"/.4000" GO/NOGO ACMETPG12 call
.4375-12 3G 12 .3958"/.4017" SET ACMETPGS11 call
.4375-12 3G 12 .3958"/.4017" GO/NOGO ACMETPG11 call
.4375-12 2G 12 .3958"/.4084" SET ACMETPGS10 call
.4375-12 2G 12 .3958"/.4084" GO/NOGO ACMETPG10 call
.3750-12 4G 12 .3333"/.3374" SET ACMETPGS9 call
.3750-12 4G 12 .3333"/.3374" GO/NOGO ACMETPG9 call
.3750-12 3G 12 .3333"/.3391" SET ACMETPGS8 call
.3750-12 3G 12 .3333"/.3391" GO/NOGO ACMETPG8 call
.3750-12 2G 12 .3333"/.3456" SET ACMETPGS7 call
.3750-12 2G 12 .3333"/.3456" GO/NOGO ACMETPG7 call
.3125-14 4G 14 .2768"/.2806" SET ACMETPGS6 call
.3125-14 4G 14 .2768"/.2806" GO/NOGO ACMETPG6 call
.3125-14 3G 14 .2768"/.2821" SET ACMETPGS5 call
.3125-14 3G 14 .2768"/.2821" GO/NOGO ACMETPG5 call
.3125-14 2G 14 .2768"/.2882" SET ACMETPGS4 call
.3125-14 2G 14 .2768"/.2882" GO/NOGO ACMETPG4 call
.2500-16 4G 16 .2188"/.2223" SET ACMETPGS3 call
.2500-16 4G 16 .2188"/.2223" GO/NOGO ACMETPG3 call
.2500-16 3G 16 .2188"/.2237" SET ACMETPGS2 call
.2500-16 3G 16 .2188"/.2237" GO/NOGO ACMETPG2 call
.2500-16 2G 16 .2188"/.2293" SET ACMETPGS1 call
.2500-16 2G 16 .2188"/.2293" GO/NOGO ACMETPG1 call

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.

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.

Gages