Help with the Union tool

I’m trying to make a couple of pipe fittings using the Solid Tools - union command and I’m not having much luck. When I try to apply the command to the selection, it’s removing geometry. All three of the cylinders are solid groups. What am I missing?

How big are the cylinders? Very likely it’s a small faces issue.You could scale the model up by 100 or 1000 and try again.

That did the trick, but leads me to another question. How do I scale up and then scale back to the same size? Is there a method to return the diameter to 2" after I use the union tool or will I need a scale ratio to get it close enough?
Didn’t expect an answer so soon, thank you.

I guess I would use what has become called “The Dave Method” and collect the three cylinders into a component. Then make a copy of the component and scale it up by 1000x, open the copy for editing, run the Union tool, exit out of edit mode and delete the giant one. Zoom Extents should take you back to the original.

I would use the Union tool in BoolTools2 instead of the native one because it seems to be more dependable and it also respects components.

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Thanks Dave. I was following an older YouTube video and didn’t notice how large of a diameter they were using (~6’). I used the method you described above and it worked great. It seems the subtracted tool worked with the smaller geometry. Why would this be?

Depends on the size of the resulting geometry. If it’s tiny as could be the case in your Y, you would have problems. I can’t tell from your screen grabs but make sure you are dragging out the radii of the circles consistently on axis. Don’t drag them out in random directions.