I really love the Smartphone cases from Quad-Lock and used them allready for the past few years. The only Problem is the Price and the Varaities of the Quad-Lock mounts. So I just 3d-printed my own ;-)

The here provided mount perfectly fits on to my bike handle (see pictures above) and holds my Quad-Lock-Phonecase extremly secure. 

I also designed the “case-side” of the Quad-Lock system, so you can print yourself a complete Quad-Lock-Package. 

I can't take credit for the spring, as I took the design from here: https://www.thingiverse.com/thing:2590838

Printsettings:

• Base and Top parts can be printed without support, Spring and Slider have to be printed with support.
• For the Spring PLA works best because it´s a bit stiffer then PETG, so it can provide more force.

Building:

1. Put the Spring inside the Slider, it should be able to compress and decompress without getting stuck. You may need to sand down the Spring a bit. 
2. Insert a M3-Nut into the Base.
3. Insert the Base into the Slider-Spring-Assembly
4. Put in the Top from the other side and screw everything together with a countersunk M3-Bolt
5. To secure the mount to the Bike, i just used Cable ties

Please keep in mind that the mechanism used, is patented by Quad-Lock. Therefore, this print is intended for private use only.