Steam Engine Modelling Details
I was confused when I was doing the meter part. So I searched online to figure out how to do topology around the area.
In this video, first is to charmer the center vertex to create a rhombus surface, and then use multi-cut tool to cut from the middle of the edges to the four corner points of the outer surface. So there will be a octagon surface. Delete the middle faces, and combine the surface with the tube, last is to bridge those edges.
After I understood how it works, I did the same steps as how it does in the video. I cut out a round shape surface on the cylinder, and then combine small cylinder with the large cylinder in order to bridge the edges. I adjust the final shape and added more edge loops to smooth it.