Weird spike by subsurf modifier I don't understand the reason for this strange spike. I tried to delete faces and edges and reconnect again several times and it's appear no matter what. What is the reason and how to get rid of it?

Here is a link to .blender file
The problem is these two vertices/edges that are connected to the faces that you're trying to smooth.  I can only assume they were part of the carryover from your screw modifier.



Delete them and this is what you get: