Step 6: Cut out the turbine and compressor blades
-Draw 3 circles with a diameter 1/8 inch less than the inside diameter of the tube on the stainless steel pan.
-Roughly cut the circles with an angle grinder or other metal cutting saw, then clean up the edges with a grinding wheel. Check that it fits in the steel tube with a little clearance.
-Drill a 1/4 inch hole in the center of each circle. This will let you connect the blades to the rotor shaft.
-Draw a circle that is the diameter of the rotor shaft in each circle. This will mark the furthest in you should cut the blades. Then draw 4 to 8 blades and cut them. I used the corners of a 1/2 inch hex nut to mark the blade spacing.
-Now bend the blades with pliers. Bend them at about 30 to 45 degrees and give the blades some curvature. The compressor blades should be steeper than the turbine blades. Bend the turbine blades the same direction as the compressor blades, but we will mount them backwards.
- Check if each blade fits cleanly in the tube. If it doesn't, fix it with the grinding wheel.