Measuring a Torus

[pjleitner]

How do you measure a torus in PC-DMIS 4.1? I need to get a radius measurement on a "U" shaped 5" diameter tube.

[rangerboat72]

I didn't even know what a torus was until I looked here:
http://mathworld.wolfram.com/Torus.html

This may give you an idea???

[rangerboat72]

How is it dimensioned & toleranced? Is it just a simple profile tolerance or are radii and other features dimensioned?

Can you upload a sketch or something?

[pjleitner]

It's a "U" shaped tube with a radius dimension to the center line of the tube. I'll see if I can get a sketch uploaded.

[cmmguy]

Measure it as a series of arcs and then construct a circle thru those centerlines

[pjleitner]

The arcs (circles) don't follow the contour of the "U" of the bend. I keep getting prompted to change the work plane to either X plus or Y plus. This puts the arcs on the X axis or Y axis instead of on the contour of the bend.

[cmmguy]

Can you rotate the Coordinate system to match the given "Slice" that you are checking?

[MrComment]

Thats looks tough, but cant you just measure the U bend as a half circle? Your only concerned with the Radius of the bend right?

Otherwise I think your stuck having to level to each slice like cmmguy mentioned.

[John Kugler]

I have a '96 Taurus if that helps.....

[pjleitner]

This is turning out to be much harder than expected. The radius dimension is called out from the center axis of the tube so it looks like I am going to have to do the slice method. So far I have been unsuccessful with doing this.

Also, this part is too big to get on our largest CMM so I am left to use a portable (Romer) CMM. This could be why I am having so many problems with this measurement.

[emkay4597]

measure a few circles from x minus after you pass 45 degrees go to y minus and so on. when your finished, construct center points (of each circle you just measured) and then from z plus use the center points to construct the over all radius.

[pjleitner]

Thanks. I think that method worked.