How many do you need? The round cuts could be made on a screw machine (programmable lathe), but the slot would need to be milled as a secondary operation. You should be able to find a switch to measure. Where is the chassis hole you plan to mount this in?
The automotive industry has been using metal 3d printing for years, to make prototype and low volume engine/automobile parts. Probably not cheap for onesy twosey, but cheaper than custom hand machining them.2) very very important, original part is metal and set screw is metal. Set-Screw is really important to tighten the Switch.
3d Printer won't work, set screw would strip out, will shred a plastic thread easily
If you have a product that these were used in, find somebody who was involved in the original design. For low volume, high end products they may have been custom made by an in-house machine shop.
These points might be overcomed in some way, some easier than others but for now it's too early to think about this
I'm still trying to find a source or more information on this part, and that's the goal here.
It's a Quest and Detective work at the moment.
3D printing will be my last, last, last resort if I don't find any leads in the next month, or maybe 2 months
I have never seen a standard part like that used on a mass market product.
If this is for use in a new product design you might be able to get a similar look with an easier to fabricate approach.
Good luck
JR