Roots blower / whats the best method to machine them?

[dale gribble]

Hi, just updated to latest release and had a quick play, I'm interested in making a roots blower to clear swarf from my mill, I've got a manual rotary table for my mill and a cnc rotary axis on my router, here are my thoughts on various methods available to me:

1, Profile cut the shape moving tool down in Z. The problem I see with this  method is limited to tool length and tool run out i.e. not square in tool holder

2, 3d machine part along x or y axis and then rotate part 180 degrees. This will give plenty of length

3 machine using cnc rotary axis on router, the problem I have is I don't have a cam for 4th axis machining currently using cambam. I see the G code that gearotic generates for the roots blower is a series of linear moves in x and y is there a formula to convert these to the a and z axis.

4, Not sure about this one but I've imported the dxf into cambam and done an polar array of lines in 1 degree increments trimed the ends to the outside shape of the blower ( see uploaded image ). I then get the lenght of these lines and use this as my z dim's and then create a subroutine

I'm thinking of making the roots blower out of nylon or acetal rod as it's no going to be producing much pressure I'm hopping they won't melt when working.

Any thoughts or ideas are welcome.

Regards

Dale