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M 10.0 X 1.25 GO/NOGO

M 12.0 X 1.75 GO/NOGO

M 12.0 X 1.50 GO/NOGO

M 12.0 X 1.25 GO/NOGO

M 12.0 X 1.00 GO/NOGO

M 14.0 X 2.00 GO/NOGO

M 14.0 X 1.50 GO/NOGO

M 16.0 X 2.00 GO/NOGO

M 16.0 X 1.50 GO/NOGO

M 18.0 X 1.50 GO/NOGO

Standard Metric Sizes

(Available in 6H class)


M 1.6 X 0.35 GO/NOGO

M 2.0 X 0.40 GO/NOGO

M 2.5 X 0.45 GO/NOGO

M 3.0 X 0.50 GO/NOGO

M 3.5 X 0.60 GO/NOGO

M 4.0 X 0.70 GO/NOGO

M 5.0 X 0.80 GO/NOGO

M 6.0 X 1.00 GO/NOGO

M 8.0 X 1.25 GO/NOGO

M 8.0 X 1.00 GO/NOGO

M 10.0 X 1.50 GO/NOGO


Reversible Thread Plug

Gages can be reversed end for end in the handle resulting in double the wear life. Each end of the handle is color coded, green for Go and red for Nogo.

Chip Grooves are provided on both ends of the Go work plug member #10/M4 and Larger.

Standard English Sizes

(Available in 2B and 3B classes)


0-80 UNF GO/NOGO           

1-64 UNC GO/NOGO

1-72 UNF GO/NOGO

2-56 UNC GO/NOGO

3-48 UNC GO/NOGO

3-56 UNF GO/NOGO

4-40 UNC GO/NOGO

4-48 UNF GO/NOGO

5-40 UNC GO/NOGO

6-32 UNC GO/NOGO

6-40 UNF GO/NOGO

8-32 UNC GO/NOGO

8-36 UNF GO/NOGO

10-24 UNC GO/NOGO

10-32 UNF GO/NOGO

12-24 UNC GO/NOGO



12-28 UNF GO/NOGO

1/4-20 UNC GO/NOGO

1/4-28 UNF GO/NOGO 

5/16-18 UNC GO/NOGO

5/16-24 UNF GO/NOGO

3/8-16 UNC GO/NOGO

3/8-24 UNF GO/NOGO

7/16-14 UNC GO/NOGO

7/16-20 UNF GO/NOGO

1/2-13 UNC GO/NOGO

1/2-20 UNF GO/NOGO

9/16-18 UNF GO/NOGO

5/8-11 UNC GO/NOGO

5/8-18 UNF GO/NOGO

3/4-10 UNC GO/NOGO

3/4-16 UNF GO/NOGO

M 16.0 X 2.00 GO/NOGO

M 16.0 X 1.50 GO/NOGO

​M 17.0 X 1.00 GO/NOGO

M 18.0 X 2.50 GO/NOGO

M 18.0 X 1.50 GO/NOGO

M 20.0 X 2.50 GO/NOGO

M 20.0 X 1.50 GO/NOGO

M 22.0 X 2.50 GO/NOGO

M 22.0 X 1.50 GO/NOGO

M 24.0 X 3.0 GO/NOGO

M 24.0 X 2.00 GO/NOGO

M 27.0 X 3.00 GO/NOGO

M 27.0 X 2.00 GO/NOGO

M 30.0 X 3.50 GO/NOGO

M 30.0 X 2.00 GO/NOGO

M 30.0 X 1.50 GO/NOGO

M 33.0 X 3.50 GO/NOGO

M 33.0 X 2.00 GO/NOGO

M 35.0 X 1.50 GO/NOGO

M 36.0 X 4.00 GO/NOGO

M 36.0 X 3.00 GO/NOGO

M 36.0 X 2,00 GO/NOGO

M 39.0 X 4.00 GO/NOGO

M 39.0 X 3.00 GO/NOGO

M 39.0 X 2.00 GO/NOGO

Taperlock Thread Plug

Standard Metric Sizes

(Available in 6H class)


M 1.6 X 0.35 GO/NOGO

M 1.8 X 0.35 GO/NOGO

M 2.0 X 0.40 GO/NOGO

M 2.2 X 0.45 GO/NOGO

M 2.5 X 0.45 GO/NOGO

M 3.0 X 0.50 GO/NOGO

M 3.5 X 0.60 GO/NOGO

M 4.0 X 0.70 GO/NOGO

M 4.5 X 0.75 GO/NOGO

M 5.0 X 0.80 GO/NOGO

M 6.0 X 1.00 GO/NOGO

M 7.0 X 1.00 GO/NOGO

M 8.0 X 1.25 GO/NOGO

M 8.0 X 1.00 GO/NOGO

M 10.0 X 1.00 GO/NOGO

M 10.0 X 1.50 GO/NOGO

M 10.0 X 1.25 GO/NOGO

M 12.0 X 1.75 GO/NOGO

M 12.0 X 1.50 GO/NOGO

M 12.0 X 1.25 GO/NOGO

M 12.0 X 1.00 GO/NOGO

M 14.0 X 2.00 GO/NOGO

M 14.0 X 1.50 GO/NOGO

M 14.0 X 1,00 GO/NOGO

M 15.0 X 1.00 GO/NOGO

5/8-24 UNEF GO/NOGO

11/16-24 UNEF GO/NOGO

3/4-10 UNC GO/NOGO

3/4-16 UNF GO/NOGO

3/4-20 UNEF GO/NOGO

13/16-20 UNEF GO/NOGO

​7/8-9 UNC GO/NOGO

7/8-14 UNF GO/NOGO

7/8-20 UNEF GO/NOGO

15/16-20 UNEF GO/NOGO

1"-8 UNC GO/NOGO

1"-12 UNF GO/NOGO

1"-14 UNS GO/NOGO

1"-20 UNEF GO/NOGO

1" 1/16-12 UN GO/NOGO

1" 1/16-18 UNEF GO/NOGO

1" 1/8-7 UNC GO/NOGO

1" 1/8-12 UNF GO/NOGO

1" 1/8-18 UNEF GO/NOGO

1" 3/16-12 UN GO/NOGO

1" 3/16-18 UNEF GO/NOGO

1" 1/4-7 UNC GO/NOGO

1" 1/4-12 UNF GO/NOGO

1" 1/4-18 UNEF GO/NOGO

1" 5/16-12 UN GO/NOGO

1" 5/16-18 UNEF GO/NOGO

1" 3/8-6 UNC GO/NOGO

1" 3/8-12 UNF GO/NOGO

1" 3/8-18 UNEF GO/NOGO

1" 7/16-12 UN GO/NOGO

1" 7/16-18 UNEF GO/NOGO

1" 1/2-6 UNC GO/NOGO

1" 1/2-12 UNF GO/NOGO

1" 1/2-18 UNEF GO/NOGO

1" 5/8-12 UN GO/NOGO

1" 3/4-12  GO/NOGO

1" 7/8-12 UN GO/NOGO

2"-12 GO/NOGO

2" 1/4-12 GO/NOGO

2" 1/2-12 GO/NOGO

Taperlock Thread Plug

Standard English Sizes

(Available in 2B and 3B classes)


0-80 UNF GO/NOGO           

1-64 UNC GO/NOGO

1-72 UNF GO/NOGO

2-56 UNC GO/NOGO

2-64 UNF GO/NOGO

3-48 UNC GO/NOGO

3-56 UNF GO/NOGO

4-40 UNC GO/NOGO

4-48 UNF GO/NOGO

5-40 UNC GO/NOGO

5-44 UNF GO/NOGO

6-32 UNC GO/NOGO

6-40 UNF GO/NOGO

8-32 UNC GO/NOGO

8-36 UNF GO/NOGO

10-24 UNC GO/NOGO

10-32 UNF GO/NOGO

12-24 UNC GO/NOGO

12-28 UNF GO/NOGO

12-32 UNEF GO/NOGO

1/4-20 UNC GO/NOGO

1/4-28 UNF GO/NOGO 

1/4-32 UNEF GO/NOGO

5/16-18 UNC GO/NOGO

5/16-24 UNF GO/NOGO

5/16-32 UNEF GO/NOGO

3/8-16 UNC GO/NOGO

3/8-24 UNF GO/NOGO

​3/8-32 UNEF GO/NOGO

7/16-14 UNC GO/NOGO

7/16-20 UNF GO/NOGO

7/16-28 UNEF GO/NOGO

1/2-13 UNC GO/NOGO

1/2-20 UNF GO/NOGO

1/2-28 UNEF GO/NOGO

9/16-12 UNC GO/NOGO

9/16-18 UNF GO/NOGO

9/16-24 UNEF GO/NOGO

5/8-11 UNC GO/NOGO

5/8-18 UNF GO/NOGO

Glastonbury Southern Gage

Thread Plugs (available in Steel, Chrome, and Carbide)

Taperlock Style: 

A Thread Plug GO gage checks the minimum major diameter and the minimum pitch diameter size in a part, the NOGO checks for the hole not to exceed the maximum pitch diameter size in a part. All GSG Thread Plug Gages are manufactured to ASME/ANSI B1.2 or B1.16M. All thread plug gages are made of oil hardened Tool Steel.