Hi torsten, you'll probably get better geometry if you make the blade one initially larger piece and then cut away a portion of that with a boolean operation rather than trying to directly model the cut away region itself separately as it looks like you are currently doing.

So something more like form the blade like this with a cutting curve drawn in the top view:




Select the blade and then run boolean difference using that curve as the cutting object:



Discard the piece you don't need:






It can in general be difficult to fillet things that are very narrow because there is not very much space to fit the fillets. Especially when things are at a sharp angle to one another or very pointy fillets will quite rapidly eat away from the surface so you may need to use a particularly small radius value on such things, and also it can make things difficult for the corner patch mechanism that deals with where fillet sections collide into one another on very pointy regions as well.

The first thing to try for filleting something like that is to continue to decrease your fillet radius, keep dividing it by tenths or something like if you are using 0.1 don't stop there go down to 0.05 or 0.02, etc...


But also generating the geometry more by a boolean cut like I show above will probably also help out since trying to build all those little pinched things in with individual sweeps will tend to make for fairly contorted and slanted type geometry and also introduces more edges into those areas which is all not good for filleting in general.


- Michael