Richard Ferguson wrote:
What method did you use to calculate the dimensions? I assume that you
did not just cut a 12 inch OD circle with a 6 inch ID, and then try to
twist it to shape. If that is what you did, you need to start over and
rethink. Please explain what calculation you did.

Richard


Bob Summers wrote:

I need help fabricating an air ramp for a cyclone - Think of
an auger flight that is on a six inch shaft (the vortex finder)
inside of a 12 inch pipe (the barrel). The air ramp doesn't
turn - it's fixed solid to both the barrel and the vortex finder.

The pitch is 6 inches per turn (it only needs to have one turn).
The ramp needs to be a snug fit to both the vortex finder
and the barrel. It also needs to be smooth to prevent
unnecessary air turbulence.

So far, I've calculated the inside and outside diameter of the
ring required to make the flight (if that is the right word)
and cut it out of galvanized iron (26 gage). The diameters seem
pretty close to correct.


You need to lay this out differently.

The inside edge is on a helix. Measure the distance from the
starting point around the shaft to the ending point. Then layout
a circle with that length as the circumfrence. Then layout the
outer line 6 inches further out.

This should give you the piece that you need.

Howard