Thank you all for your feedback about the undercarriage!
FittingsIf done with wood, I should add metal too.
That means fittings. Soldered thin brass foils together to do some parts at once.

Additionally two other kinds.

Mounted view. I can put the suspension between the "bolts" (0,33mm nickel silver).

In the front it just hold the strut. The instant glue will stabilize the wooden frame (I hope).

Still not done! Two plates with hole and 0,2mm axle ...

... steers the half axles during rebound. This is shown in a drawing in Datafile.

And if I do sheet metal forming ...
I found a picture of the open front in the internet:

Quelle: postimg.org
I tried to build that part as far as I could.

The bearing is turn from brass on my lathe. Since I don't own a dividing head some of the small holes are not distributed equally, but axle and air screw will block part of the view.

After a tin-coat it looks much better.

I will solder the parts from back.

Such small parts could eat up a lot of time, and I never constructed or made myself PE parts.
Cheers,
Frank