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STOCK FINISH: The most used of any gasket finish practically is suitable for all ordinary service condition. This is a continuous spiral groove. Flange size 12"(304.8mm) and smaller, are produced with a 1/16"round- nosed tool at a feed of 1/32" per revolution. For size 14"(355.6mm) and larger, the finish  is made with 1/8" round- nosed tool at a feed of 3/64" per revolution. Spiral, Serrated or Phonographic: This finish a produced by using a 90 round-nosed tool.

Concentric Serrated: This finish a prduced by using a 90 round- nosed tool.Smooth finish: The cutting tool employed shall have a approximate 0.06" radius. The resultant surface finihs shall have a 125u inch to 250u inch(ANSI B16.5 para6.4; 4.1)

1. Raised Face and Large Make and Female Either a serrated-concentric or serrated- sprial finish having from 34 to 64 grooves per inch is used. The cutting tool employed has an approximate 0.06 in radius. The resultant surface finish shall have a 125u inch(3.2um) to 500 u inch(12.5um).

2. Tougue and Groove and Small Male and Female:

The gasket contact surface does not exceed 125u inch(3.2um) roughness.

3. Ring Joint: The inside wall surface of gasket groove does not exceed 63u inch roughness

4. Blind: Blind flanges need not be faced in the enter, whenb this enter part  is raised. Its diameter is at least smaller than the inside dia. Of fittings of the corresponding pressure class. When the center part is depressed, its dia.is not greater than the inside dia. Of the corresponding pressure class fittings, maching of the depressed center is not required.

When the thickness of the hub at the bevel is greater than that of the pipe to which the flange is joined and the additional thickness is provided on the outside
dia. A taper weld having a slop not exceeding 1 to 3 may be employed or alternatively the greater ourside dia. May be tapered at the same max.slope or less, from a point of the welding bevel equal to the OD at the mating pipe. Similarly, when welding the greater thickness is on the inside of the flange, it shall be taper bored from the welding end at a slope not exceeding 1 to 3.When flanges covered by this standard intended for services with light wall, high strength pipe, the thickness of the bub at the bevel may be greater than that of the pipe to which the flange is joined under the conditions a single taper hub may be provided and the outside dia. Of the outside dia. Of the hub at the base may also be modified.
The additional thickness may be provided on either inside or outside or partially on each side, but the total additional thickness shall not exceed one-half times the nominal wall thickness of intend mating pipe