Fig 1-30 quick understanding

[gabimo]

ASME Y14.5-2009/ page 15
1.8.2 states: Where the center of a radius is not dimensionally located, the center shall not be indicated.

Fig 1-30 ASME Y14.5-2009
Why the center of the radii are indicated?
Aren't they shown by the two small crosses?

 

[Belanger]

I guess we could be charitable to the ASME committee and remind ourselves that the figures in the standard are not complete -- they only illustrate a specific point. It seems that Figure 1-30 is emphasizing the specific point from paragraph 1.8.4, not paragraph 1.8.2.


John-Paul Belanger
Certified Sr. GD&T Professional
Geometric Learning Systems

 

[gabimo]

Thank you J-P.
So, do you agree that is a bad practice (somehow in a disagreement with the previous paragraph) to show the two small crosses?
I am not nit-picking the standard (is made by humans after all), but I am learning the best I could.

 

[mkcski]

gabimot:

Be aware: radii without located centers are to be tangent to the adjoining surfaces. So no centers should be depicted if this is the intent.

Certified Sr. GD&T Professional

 

[gabimo]

mkcski,
I agree with you about the tangency.

1.8.2.1 also states:"Where a dimension is given to the center of a radius, a small cross is drawn at the center." ..........
"Where location of the center is unimportant, the drawing must clearly show that the arc location is controlled by other dimensioned features such as tangent surfaces."

Fig 1-30 does not have the radii centers located nor the tangency implied so I am not sure why the two small crosses are shown or will be more "correct" way to show the picture WITHOUT those two small crosses.
Or someone will argue that "in the real word" the distance between the crosses must be shown.

 

[pylfrm]

gabimot,

In ASME Y14.5-2009 Fig. 1-30, the small crosses at the radius centers are shown coincident with the horizontal center line of the slot width. It could be argued that they are serving to indicate an implied zero dimension for the relative vertical location.


pylfrm