Here you see the results of using the collett adapter:
The engraving on top is done by a 1/8" 30 degrees engraving bit, placed in the router with the mentioned adapter in the stock 6 mm collett.
It honestly works quite well. Once the mill dropped down into the work piece, very much likely because I didn’t tighten the collett screw enough.
But I wonder - would the results be even nicer with a proper 1/8" collett from Elaire?? Who knows? Is it worth it? http://www.elairecorp.com/makitaroutercollets.html