Gert, almost invisible wooden hinges are doable by those with patience! The trick is to make some 1/4 diameter dowel out of the same timber as the box. Cut this into 5 pices that add up tp the complete width of the box. You do need a jig to drill a 1/16 hole about 3/8 into each end or use a lathe and centre drill. Next run a groove on both dides of the hinge joint (this is tricky for one off but a cinch in production) and a 1/4 ball nose works really well. The idea is to make this 1/32 deeper than than the outside of the 1/16 hole so that when the round bits sticking out tye back get planed off the hinge wire doesnt break though. You glue up one side of each piece and stop excess by using wax. This all sounds horrifically fiddly but it adds super class to a project. Big box dowell is usually garbage which is why you make your own. These hinges are super strong as they go full length and you dont need stop chains etc. The best part is showing to your woodie mates and watch them scratch their heads as it initially had me totally tossed!! This method would lift your already fantastic boxes up into tye $300 plus class. Cant post a pic at present as since IOS 8 it wont let me post.
Buddy BT48 with 6' power stick
2.2 HSD Spindle
Aspire 9.5
6" ShopBot Indexer