How to check cylinders or diameters at a specified angle?

[Martin_77]

I am having trouble checking a diameter at a certain angle. I created a plane across the face of the diameter; then I measure a circle. I project a point to the circle, but i don't understand why my diameter comes out small and it does not regestered at that angle. Please help!!!! I did use my working plane pull doen menu. There is a tube that is 40deg from center line and cannot measure it correctly...

[rangerboat72]

It is not perfectly clear what you are asking here. You may want to upload an sketch or a drawing view to clarify your question...

What is the diameter measuring before you project it into the plane?

[William Johnson]

If I understand what you are asking I would add are you in the right work plane, and is your current alignment perpendicular to the circle that you are measuring. If not your circle wil be eliptical.

[#2#]

It sounds to me like you have a hole through a part which is set at a 40º angle to the face of the part.

I assume you have rotated the probe to allow good, non-shanking hits all around the hole. If you measure the face of the part as a plane and align to it, offset the alignment by ±40º so that the vector of the hole will be 0,0,1 (or 1,0,0 or 0,1,0) Then, measure the hole as a circle or whatever. That should get you an accurate diameter (or as accurate as you can get with your cmm and the part, blah, blah, blah). You can not dimension the angle of the circle. It will not give accurate results with only one row of hits - it will always show nominal.

Of course, if you measure your hole as a cylinder instead of a circle, or use an autocircle, you should get better results without offsetting the alignment. A cylinder would give a good angle measurement, an autocircle wouldn't.