Thanks for the source. Problem is Their minimums and handling fess are GROSS. I need sixteen inches of this stuff. I can't spend seventy plus dollars plus shipping...
Many errors here:
1. Heavy section at base of stud and around hole. Revise to constant wall.
2. .004 interferance out of .09375 is too much.
3. 3 degrees is way too much. Consider 1/2 degree.
4.Fits like this will invariably fail over time due to relaxation. Use solvent bonding instead.
Everybody has missed a point: A helicoid is not developable!
A closely related surface appropriately called a "developable helicoid" exists. The straight line elements are not radial as in the helicoid, but are tangent to the inner cylinder. A real excercise in descriptive geometry. I think...
I'm gonna write it before anyone else has a chance: Don't reinvent the wheel! There has to be wheels available at low cost, so you need not go through design, mold build, first shots, mold revision etc.....
Adding to what Greg locock wrote, one reason design for under water is less finicky than design for air is that water is far denser than air, making Reynolds numbers lots bigger.
The fixture is simple. I spent $2.31 for some wood and used an electric stapler that was on hand. I hacked it on my kitchen table. Took most of a day. Works a dream!
