Third try at button:
I started by making a mini-buck to shape the metal around. This began with using the band saw to cut two pieces of dowel, a 1 1/8" diameter and a 1 1/4" diameter piece. (Yes, they should be identical, but I messed up the handle, and I'm building the button to match it.)
Next, cut part of each dowel away. I was going to do this with the band saw, but it made a funny noise when I put it vertically, so I decided to leave well enough alone and cut the excess off with an angle grinder. Naturally, the cuts were a little on the crude side.
I rubber banded them together, rummaged around for some screws, and used the drill press to drill some holes for the screws. Then I screwed the two pieces together
The screws were too long so I the angle grinder again to cut the tips of the screws off. Then I took JB Weld putty and filled in the cracks between the two dowels. A little sanding, and the mini-buck was complete
Next, I cut the metal and bent it around the sides of the mini-buck
I made it slightly longer than needed so I could later trim it for a better fit.
I repeatedly alternated between hose clamps and tin snips as I snuck up on the exact size needed for the metal side of the button.
The sides were trimmed, welded together, and ground smooth on their outside surfaces. Afterwards, many small cuts were made to the top edge of the button, and that edge was bent inward with locking pliers.
The rough edges and peaks of the edge were ground down with an angle grinder. This edge provided a larger surface to weld the flat end piece to.and grinding gave a nice beveled edge.
I then put some low temp moldable PCL into water, boiled it in the microwave, and shoved it into the cap while it was malleable. I then stuck a 5/8 dowel in the middle to make room for the depressable top of the gear selector to fit into the button.