I am currently working on a needle that needs to be cut with a double helix.

I have found plenty of useful videos depicting the most basic helices, but I am needing a more complex explanation of how to achieve my end goal.

My problems arise when getting to the tapered nose of the needle. The cut does not come out clean on the nose, no matter what I do.

I have tried intersection curves and a whole assortment of other things, but nothing has work for me so far.

As can be seen in the above picture, this is what I would like (the colors just distinguish the two helices).

In the cylindrical section of the needle everything is just dandy, but as it gets to the needle nose the whole things breaks down and starts to look very strange.

The gray is the material left to separate the two helices, but in the nose there is no consistency with the cut.

Could someone please help me fix this issue? I am getting super frustrated trying over and over again to no avail.

Thanks in advance,

DW