Hi Lukacs,
Nice work. The faces on that whasher, shaft an compressor is super important. On all these you need better than +- 1uM. Very difficult with turning, actually impossible. With grinding or even hand lapping with 2400 water paper on glas you can do it with light oil as lube. The most important tools are 1uM micrometer and dial gage. Also make sure your shaft is push fit at 150 - 200 deg C of compressor.
If these tolerances are not met balancing is difficult and bearing life will suffer.
I have attached picture of how I do glowplug nut. The nut has step at bottom, the hole in cc allows for front back slide due to expansion. The nut is brazed onto Ss strip which covers the elongated hole and attaches to front of CC. Later we put kink in strip for some "spring'.
This way the braze do not get hot and the joint will not crack. Also alignment is easier. Note the countersink of nut at top. Makes replacing glowpug easy as it guides thread.
You do not want airgap at nut cc interface. It makes gas start difficult, even kero start is better this way.
Andre