Nominal and Finished Thickness

Hello yeonhoyu,

Very good answer. Polite and straight to the point.

Agree - nice to have an answer that does not just say "why don't you google it" or "why do you want to know".

Excellent answer in post # 1.

In the more general sense, nominal means "in name." So nominal thicknesses (or sizes) of anything are the named size. In the US system, a nominal 1" shaft or piece of bar stock may measure several to many thousandths bigger or smaller than 1.000". In several cases, the differences are dramatic, as in pipe, where a nominal 1" pipe is not very close to one inch on either the inside dimension (which is the dimension the pipe is generally named for) or on the outside. This goes to extremes in naming our classic building lumber, the 2X4, which is nominally 2" x 4" in cross section, but actually measures 1.5" x 3.5."

Hi guest,

A factory product of say wood, steel, or metal has a 'Nominal thickness', this then goes on to other processes where that 'Nominal Thickness' is brought down to a 'Finished thickness', after the metal has been ground or has had an edge put on it and other finishing has been done.

In Wood or Lumber, the nominal thickness can be several times the finished thickness. Where you need a finished thickness of 2" x 1" (50 mm x 25 mm),

The initial tree is cut to a Nominal size of ~ 11.75 x 4.75" (~ 287 mm x 118 mm)

Then this goes onto another factory perhaps.

Cut to its finished size of 5 x 2" (50 mm) pieces and, 4 x 1" (25 mm) pieces.

At a finished size of 2" x 1" (50 mm x 25 mm).

So from the initial nominal size you get 9 finished lengths.

This is often true of wood where it is green and has to be dried. They dry it in its Nominal size then work on it to get finished wood for home building and second fix. Where it is dried before finishing, as it dries it shrinks, so the nominal size may be larger that I have hypothesized to allow for the shrinkage.

Hope this helps!

Hai all

When dealing with Hemispherical dish heads, is this nominal/min value is considered?

Is there any knuckle reduction in hemispherical dish heads?

I mean with which value we are drawing the dish thickness in GA Drawing (nom. or min.)

Regards

Wijeesh