Yes a step has to be machined on the bottom side of the perch for the switch body to set in. You also have to drill a hole for the plastic pin on the switch to set in. To make the pin hole I made a crude jig to guide the drill bit. Needed to do that because you are drilling at an angle compared to the housing.
View attachment 135037View attachment 135038
For the pivot bolt hole I drilled it with a 3/8s drill bit to the depth I wanted. This does not leave a flat bottom hole. I then used a 3/8s end mill to mill the bottom flat. If I had a real mill and better clamps I would have skipped using a drill bit first. If a guy had a real steady hand you might be able to do this with a hand drill. Fortunately for me I have a cheap drill press.
View attachment 135039
View attachment 135039View attachment 135040
Yeah! There you go. Nicely done, I like that much better than my pressure switch!