Knuckle Radius for 2:1 Heads

[weldtek]

Code paragraph UG 32 (d) says that the shape of a 2:1 head can be approximated by a head with a knuckle radius .17D, and a spherical radius of .90D. UG 81 (a) provides tolerances for formed heads and says that the knuckle radius shall not be less than that specified.
Is 'that specified' .17D. Does this mean that the knuckle radius can be .17D +/- the tolerance provided in UG 81(a)?

 

[vesselfab]

every manufacturer uses a different radius formula for a 2:1 elliptical head. it can be .17d +/- te tolerances shown.

if you want to check that close, get the head manufacturer to furnish his dimensions and check to those.