Inductive distance sensor and glass 3d printing plate

Long story short, 8 mm inductive distance sensor will not sense an aluminum plate from 4mm. Steel, yes, aluminum, no. Slightly more info, but not this specific piece, in the video link hidden in the text below.

I am working on making a 3Novatica Gate 1.0 printer more usefull, and one of the things I added was printing out this pretty useful ducted fan mount:

It really improved the print quality with overhangs, slopes and pretty much all surfaces. I noticed it has a hole for mounting a bed distance sensor for auto-leveling, and calibrating the bed many times I started wanting to add that part. I ordered LJ18A3-8-Z/BX which was inappropriately labeled as having 12 mm diameter (and I didn’t notice the part number suggests it’s actually 18mm). The holder I printed has a mounting hole of 12 mm, so I needed to adapt the part. When I did, and printed it out, I mounted the sensor and tried to see what distance to set it for. As I learned from this awesome video, comparing different distance sensors, these sensors are made to detect steel, aluminum has different qualities and will be detected from less than the indicated distance. Okay I thought, the glass is 4mm thick, the sensor senses steel from 8mm, I should be well within the range. Well, turns out it wasn’t.

Extruder assembly