Do-it-yourself mechanical thickness gauge couldn't be easier

A super simple magnetic-mechanical thickness gauge that absolutely anyone can assemble in about 15 minutes. Incredibly, with this simplicity, the device has amazing sensitivity and can detect changes in the thickness of paint coatings of the order of 0.1 mm.

The operation of the device is based on the force of magnetic separation.

Will need

Unnecessary headphones.
A pair of plastic tubes from drills. The main condition: one must fit into the other.
Stationery eraser.
Self-tapping screw.
Super glue.
Insulating tape.

Manufacturing of thickness gauge

We open one of the headphones.

We tear off the small neodymium magnet, which is located in the center behind the membrane.

Glue it to the screw head with super glue.

Wrap the thread of the self-tapping screw in one layer of electrical tape.

Then we wrap the elastic band.

There is an angry hole at the end of the plastic tube. Next, a self-tapping screw with a magnet is inserted, and the rubber band is threaded through the entire tube.

Next, one tube is inserted into the other.

The end of the rubber band is fixed with a cap from the same tube.

Now it turns out that one tube comes out of the other with force, and jumps back when released. We apply divisions with electrical tape.

You can check the work:

How to use a thickness gauge

A thickness gauge will essentially measure the force of magnetic separation between the magnet and the metal of the car. That is, we magnetize the magnet to the car body and pull it back. Naturally, the middle part will come out of the tube. As soon as the force reaches its limit, the beckoning will break away from the body and fly back into the tube. This limit of its extension will show the approximate thickness of the paintwork.
Example: A car with factory paint.