buy some liquid rubber (and hardener) and mix it thoroughly
place your originals in a (plastic) cup or so, widest part on the bottom, all parts at least 1 cm from the edge and from each other
put the liquid rubber in the cup (the stick shown in this pic is to create an axle in my gear, let it harden for a couple of hours and remove it from the cup.
Remove the originals and the mould is ready
picture still to come
buy and mix the liquid plastic, put it in the mould and let it (in my case) harden for at least 15 minutes before removing it from the mould
the black and white stripes can be made with a printer and white printable etiquettes (or paint and a brush ofcourse). The used etiquettes are shown on the right side.
stick the stripes on the (now painted and drilled) knob and spray a layer of varnish on top of it. On the right hand a knob straight from the mould, in the middle the painted and drilled knobs and on the left side the ready knobs.