I been trying to draw this lower part but I can seem to get the curves

I was able to revolve the upper part, but failed to draw the part with curves. How do I best draw it u help will be appreciated.

2 Answers

John, You have a good start. You just need to set the size of the 3 arcs and make them concentric to the center hole. I guessed at the R 63, like Carlos said. Then do a little trimming and you got it!

here is a little more help. Do some trimming and you should be all set.