Spherical radius 1

[sudhakarn]

Hi folks,
I want to understand the concept of spherical radius (SR).what is the difference between radius and spherical radius?Could you please share some insights? thanks in advance.

 

[monkeydog]

If you google "spherical radius vs radius" you will get some real nice responses.

 

[Tmoose]

https://ds055uzetaobb.cloudfront.net/image_optimizer/cf122223ecdeb31d0acbcb163505c2919c537e8c.jpeg

 

[sudhakarn]

Hi Tmoose,
Thanks for your interest.could you pls explain me this image?

 

[ornerynorsk]

Isn't "spherical radius" more or less self-explanatory??? If you section a 3D object that has spherical curvature into a 2D planar view, it is simply the radius of said curvature.

It is better to have enough ideas for some of them to be wrong, than to be always right by having no ideas at all.

 

[sudhakarn]

Hi ornerynorsk,
Thanks for your reply.I want to basically umderstand the reason behind the term spherical radius and why it is not called a mere radius like in ordinary cases.
P.S : I am not very Strong in drawings.kindly request you to guide me.

 

[hydtools]

It is just the difference between 2D and 3D. In the planar world, 2D, the term radius is used to describe the distance from a circle's center to the circle's circumference. In three dimensions, 3D, the term spherical radius is used for the distance from a sphere's center to the sphere's surface.

Ted

 

[BrianE22]

"Radius" is often used in a 2-d sense to specify the radius at the intersection of 2 surfaces. As mentioned, "spherical" generally refers to a 3 dimensional feature.

 

[sudhakarn]

Hi folks,
Thanks a lot for your replies.can we conclude that spherical radius indicates spherical surface when mentioned as SR?

 

[monkeydog]

sidhakarn,
Based on your original post SR means spherical radius.
Other requests for additional information, I am a bit perplexed as to what information you are hoping to gain from this thread.

 

[sudhakarn]

Hi folks,
What i undeestand is spherical radius is the radius which is same along the two planes unlike a cylindrical radius.please correct me if i am wrong.

 

[hydtools]

I think you need more fundamentals in plane and solid geomtry.

Ted

 

[sudhakarn]

Hi folks,
Thanks for all your replies.Now i have understood the concept.hope i will get it better if i put it in practice.

 

[chez311]

sudhakarn - i think the trouble that you are having is you are thinking of it from a purely geometrical/mathematical perspective. in geometry regardless if you are referring to a sphere or a circle you typically just use the term "radius".

the only reason for the addition of the term "spherical radius" in the 2D drawing/drafting world is to more clearly denote on a drawing what is being referred to - it is often not immediately obvious when a feature is actually spherical from looking at a 2D view so the term spherical radius and the symbol <SR> is utilized to make this clear in engineering drawings. see the below application from the Y14.5-2009 standard - one might be able to infer that its a spherical feature on the end, however when creating drawings one needs to be as unambiguous as possible to prevent confusion - hence the term spherical radius. also FYI this would be a better question for the "Drafting Standard's, GD&T, and Tolerance Analysis" forum

https://www.eng-tips.com/threadminder.cfm?pid=1103

 

[sudhakarn]

Hi Chez,
Excellent!Thanks a lot for your insights.

 

[smptrsn]

Radius : the distance a ray extends perpendicular to an axis anywhere along that axis

Spherical radius : the distance a ray extends in any direction from a single point in space

 

[enginesrus]

If you are looking at a ball any ball that is symmetrical, not a foot ball. But more like a ball bearing. That is a spherical entity. Others here have described what the radius is of that spherical ball or entity.
Now if you use a compass and draw a nice circle on a piece of paper, that is the 2 dimensional view and if you draw a straight line from the center point where the compass point was put, to the curve of that circle that line represents the radius.
If you use some thing to measure the ball on the outside and find the largest points by moving the measuring tool around to find them. You simply take that measurement and divide by 2 and you will have the spherical radius.
A sphere every point on its surface is equidistant from its center. And if you cut that sphere in half in any direction you choose, and look at that cut straight on perfectly square to the cut, you will see the 2 d radius that you just used the compass to draw. Is this a simple enough explanation?