If the concentricity of the crankshaft is drilled by hand, it's prone to axial deviation. Chen Zhou plans to modify the angle grinder slightly to make it a small hand drill for drilling.
The precision problem of bearings is also solvable—
Bearing can be dismantled from both the big anniversary gift pack and some metallic items previously sent. He just needs to select the most suitable size and specifications and customize the crankshaft for them.
Of course, if subsequent rewards include a batch of bearings, it would be even better, allowing for more flexible design of the steam engine's dimensions.
As for the gap between the cylinder bore and piston, Chen Zhou doesn't have a very good solution.
For precision ≤0.05mm, he can only try to hand-grind it, and whether it works or not still depends on skill.
The contact surface of the slide valve and valve seat also relies on handwork, requiring a flatness of ≤0.02mm, which is quite a challenge for Chen Zhou.
