Hi Shazbot, I've attached here a 3DM file with a tuned up version of your object with those cylinders simplified, and also the little top face removed (I duplicated the edge curve you had and edited the top of the curve and did a revolve to make a smooth tip), and this should fillet now, it doesn't have the difficult multi-edge juncture areas that you had in your previous model.

You will be limited to a pretty small fillet radius though still - it won't work to do much more than about 0.06 units for the fillet radius, because there is not enough room to fit a fillet larger than that without the pieces running into each other in these tight areas here:






If you wanted to put on a bigger fillet than that, those cylinder pieces would need to go up a bit more and also probably stick out just a bit more, otherwise there is not enough room for the fillets to actually fit in the space you've got there.

- Michael