Some time ago I purchased a Hi Mound HK 804 I was quite interested in the construction and so thought I might try an experiment using a similar idea,  in the HK-804 it is basically a single spring idea similar to the Swedish key where the spring acts as a pivot and is biased with another part of the spring under an adjuster, I've tried that idea before a few times and its ok but the action always seems a bit stiff when on a light setting, I much prefer the bias to be a light coil spring as in some of my early keys, but with this key I shall stick to the HK-804 idea only with a slightly different approach so this key will be a G3YUH version of the HK-804 design as usual :)) here the pivot springs are fitted into milled groves, these high tensile springs are cut from windscreen wiper blades and are as tough as they come but small and light even at this very early stage it feels nice which is a good sign.. I shall use one of the springs as a preset coarse tension adjustment and the other as a fine, here it is ready for first tests, it mimics the feel of the HK-804 almost exactly, possibly a bit more follow through after the contacts close though that can be adjusted in the assembly,  a very nice action if you like these spring pivot keys, just needs contacts fitted, really simple but very effective key to make, a little delicate to be honest, not the sort of key to be handled roughly, but if you want a fine key then it has to be that way sometimes, food for thought :()