Step 4: Make the Rotor Shaft
-Mark the length of the steel rotor shaft. Mark it 1 inch shorter than the center tube (the center tube should be 2" longer than the combustion chamber) and put marks on the shaft where the center tube will be cut. Cut it at the length you marked. Grind the last inch or so to a point.
-Shave the middle part of the shaft that will be between the bearings down to 1/4" to take off some weight. Then drill a 1/4 inch diameter hole about 1 inch deep into the end of the shaft in the front.
-Put the rest of the 1/2 inch diameter steel rod in the lathe and take a 3/4 inch long section at the end of it down to just under 1/4 inch in diameter. This will be a pin to slide into the hole in the front of the shaft. Then cut the rod off 2 inches behind the pin you just made and smooth off the end. If you are using an electric starter, drill a hole into the end of this piece that will accept the motor's rotor shaft. If not then you can grind the front of this piece to a point.