Improve Taper Fit, make shell thicker and sturdier, and make chambers larger...

[RobertLRead]

I don't expect this to completely make sense without much more discussion. Based on my most recent discussion, I believe the OpenSCAD system should be improved by:

1. Making the trap chamber larger, so that particles are less likely to be re-picked up.
2. The shell is too think and cracked; it needs to be made thicker to be sturdier.
3. The taper fit between the paper filter holder and the inertial filter holder is not very good; this should be standardized.
4. This helix may be too large. I made it large because I had trouble with the laser sintered 3D print from xometry, which was clogged with powder. I had to build a conical reamer for it. (Though the advantage of this is that it was dry, and not very sticky.)