Constructed line on same workplane

[sleepystarz]

Hello, first post here. Our CMM operator has left and they've thrown me into the mix after 1 week of training. I'm learning a lot but still have a ways to go.

Currently inspecting a crankshaft and having problems with a constructed line. I'm creating the line from center-to-center of 2 circles but would like to flatten the x-axis workplane to draw the line. I think it's currently drawing the line from the real locations.

Sorry if this is poorly explained. I'm constructing this line to find an angle deviation from another line already drawn...thanks for any help!

Billy

[Wes Cisco]

My best advice is to construct a 2D line in the Z+, Y+, & X+ workplane then examine them in your graphics window. Rotate the graphics around on the screen, keeping an eye on the trihedron so you know which way your axis are pointing. One of them will be what you need and this will help you to understand how workplanes control 2D lines. Once you have the line you need you can delete the extras. Do not use a 3D line for what you are trying to do. HTH

[than_357]

Along with constructing the line in the workplane that the axis would be in, you'll want to measure the angle of the lines in the same workplane that both lines are in. Otherwise you'll find some odd angles. The graphic view will show you if your line isn't constructed right as mentioned in the previous answer but the only clue regarding the angles will be what you see for a value.

(note- in case you're confused by the 'trihedron' reference; it's the graphic display of the x/y/z axis in the graphic display window)

Tom

[sleepystarz]

Thanks to the both of you! I drew the 3 lines and viewed the display on the right...very helpful. Found that I needed to be working in X-plus to get the correct line. You couldn't have explained it simpler for me. Tom, I'll remember to get my angles in the correct workplane for both the lines.

Now I need to get the distance from these two circles center-to-center and also getting some funny numbers. What seemed to work was to get a 3D distance dimension but for now I'm using an optical comparitor until I can trust this dimension. Any thoughts on if using 3D for distance dimension would get me accurate distance between these two circles?

Billy

[sleepystarz]

Update, I got a distance using 3D and also using 2D in the correct workplane and came up with the same number. I'll keep practicing working in the correct workplane and look more at the graphic display on the right from now on...thanks for everything guys.

Billy

[than_357]

Glad it helped. An argument could be made to limit use of distance measurements since they are center to center of features and if not in the same plane you could get the diagonal (straight line) instead of axis distance. If you can picture the distance 2D in the workplane you select (and you have the origin on one of the features), then a simple location callout will suffice.

(eg- zero x/y/z on one feature and then show the location of the other feature in the axis which is relevent)