Measurement, Am i doing the math wrong?

[Jake.Scott737]

I want to make a Cylinder, will say 150mm on the outside Dia, 5mm high. Then I want to cut a hole in this object 140mm in Dia, 5mm high. Why when i get done doing this does it not leave me with a 10mm Ring 5mm high? It comes up 5mm's

Am i loosing my mind. or did some how they how change math?

[JDMather]

150-140=10

10/2=5

Can you Export your *.f3d file and attach it here?

5+5=10

[Jake.Scott737]

Not sure where the file is i saved it but can find the File

[Jake.Scott737]

though the First example is what i am saying is happening. why is it only 5mm wide and not 10mm wide?

[Jake.Scott737]

here it is 

[Jake.Scott737]

the math of 10/2 = 5 is wrong. that is a Radial Measurement. 

[JDMather]

Are you familiar with the definition of

Radius

Diameter

in geometry?

[jeevesme]

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@Jake.Scott737 wrote:

though the First example is what i am saying is happening. why is it only 5mm wide and not 10mm wide?

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Because the outside circle is 5mm away from the inside circle.  You are using the term "wide" when you should be using "offset".