Universal Batteries Testing Holder (AccuFrame)

If you have a deal with a lot of gadgets and batteries it is a good idea to know what batteries are good and what are out of resource.

The testing routine is well-known (charge-discharge while measuring the capacity) but what is really needed is:

The Universal Battery Holding frame with spring loaded contacts.

To make one you need to print all parts and prepare:

1) 4x M2x20 screws + 4x M2 nuts + 10x washers
2) 2x M3x30 screws w/hidden head + 2x SelfLocking M3 nuts
3) 80mm lengts 4mm2 single copper wire (to make the contacts) (OD=2.2mm)
4) 2x springs: OD=4mm, ID=3mm, L=25mm (from some cheap pens) - for contacts
5) 3x springs: OD=5.5mm, ID=4.5mm, L=17-20mm (from the springs kit) - to assemble the Platform

The ghosted overview image: copper contacts are in orange, springs in blue.

A) Make the contacts according to the image attached (bend and solder the M2 washers as the spring stoppers)
B) Solder wires to the contacts topmost ends
C) Assemble the Contacts Parts (C