Inside diameter.

Threads per inch.

1/8

27

1/4

18

3/8

18

1/2

14

3/4

14

1

11 1/2

1 1/4

11 1/2

Inside diameter.

Threads per Inch.

1 1/2

11 1/2

2

11 1/2

2 1/2

8

3

8

3 1/2

8

4

8

Taper of threads, 1/16 per inch of length. These inside diameters are only estimated, as they vary for pipes of different strength, the thickness varying for the different grades, and the outside diameter remaining the same.

Piston-Rings, To open-Hammer them lightly with a round pene-hammer all round their inside faces.