Lock or fastener for QG10-15 plate

Lock or fastener for QG10-15 steel plate. This fasteners are used for my zero point angle:  https://www.printables.com/model/1269960-zero-point-angle-for-a-qg10-15-steel-plate-rectang

Be aware there are two different headers. The small one is for the angle. The bigger one if you want to use it stand-alone. You need M4 melting insert 4mm height. I use a screw to fasten the insert, but you can use any kind of M4 thumb screws. I use superglue to connect fastener with the head.

The fastening element works like a leaf spring. I uses PETG but PLA should work too.

Infill for header: honeycomb; 25%

Infill for fastener: straight line (in the longitudinal direction), 30%; 
perimeter: 2; base&deck layer: 5; support for the holes

I've added another header for M4 countersunk screws if you need them

Attention: As always with my designs, you need a well calibrated printer. The tolerances of my designs are tight. No room for failures.

As a complete other successfully used  idea: alternative you can use a 10mm rubber hose with a washer too. When you tighten the screw the hose is compressed and expands. That locks the cover element in place.