Difference between nominal and finished thickness

[s1111]

What is the difference between nominal and finished thickness?

Thank you.
s1111

 

[0707]

from my understanding nominal is the nominal size thickness

finished thickness is the nominal thickness plus or minus the tolerance

luimarques

 

[chaulklate]

We use the term 'finished' thickness for parts that are rolled or formed; shells, heads, nozzle necks. During forming, the steel has a tendancy to thin out in areas, most common in the knuckle area of heads. As any one component is only as strong as it's weakest part, the 'finished' thickness will be the value used for calculations. Example; you may start out forming a head with 1/2" plate (that is the nominal value) but the knuckle may be only be 0.4375" +/- when complete (this is the finished thickness).

 

[s1111]

thank you much chaulklate and 0707.