Hercus lathe tachometer sensor mount

Mount to fit a hall effect taco sensor to the rear gear cover which attaches to the bracket for the outer gear cover on a 9" Hercus lathe.
Mine is the craftsman version of the Hercus 9" which has a slightly different headstock from the standard herbs 9A, 9B 9C, although I believe that the gear cover and gear cover mounts are all the same. I am note sure if the standard 9A, 9B or 9C lathes share this inner cover or not.
This mount is a slip fit on the top corner of this cover as per the photos. I have included a threaded hole for a 3mm grub screw, but this is not essential.
Initially this was a tight spring fit, so I also made the included spacer piece which sits on top of the bracket for the outer gear cover, and spaces out the inner cover from the gear cover mount. This takes the stress out of the fit, and it goes together more comfortably without any spring.
Not the the top edge is cut away to allow the outer gear cover to close.

A rare earth magnet is glued to the bearing thr