I'm trying to add more and more details to my workshop design, I just move here a few months ago, in my fathers workshop and I need remove alot of things (old furniture) and add new things, tables, shelfs, workbench .. etc.
I modeled the cast iron radiator, it came out almost as the original one, I didn't knew how to make the chamfers around the edges of elements more sharp, the real radiator is not that rounded, the elements are sharper, the chamfers are not made by a quarter of a circle (the default chamfer) but rather a guarter of an elipse .. but that's ok, it doesn't bothers me, the other thing it's quite annoying and maybe I did everything the wrong way, is about the moment when I want to add new details to a component I made, do I need to ALWAYS ADD A NEW PLANE ?
In the screencast bellow I wanted to add the small 16mm circle you see I'm hovering at the beginning, but when I first did it I tried to select the plane, by selecting the larger circle face, in the video it's the second circle I hover over, but this made the pipe in the right dissapear as the timeline moved back a few steps 
, after that I added a new plane (the third thing I hover in the screencast) and start creating the small 16mm circle on that plane, this way it worked as expected.
So again, my question is always do a new plane when adding sketch to an existing design, rather than selecting the face of an object as the plane ?
Thank you in advance.
