RE: DLE222 Starter System - The Project
Now on the crankshaft itself,
Find a suitable steel (something like 18 or 20mm diameter), machined one end of it a bit to make 8mm extrusions. This extrusion will use to align the rod to the crankshaft. Press it in (be careful here always put something between the flywheels if not you may bend the crankshaft).
Using TIG (Tungsten Inert Gas) welding, weld it's circumferential join. A bit extra here and there no problem. Put the whole assy to lathe machine. Lathe it out to 16mm diameter exactly.
Refer photos below.