In today’s episode, we’ll look at the crankshaft assembly.
I changed the design of the crankshaft from a one piece to a built up design. I feel a built up crankshaft has the advantage of being easier to build and can produce a strong, true running shaft. Another advantage is, that we can use a needle roller bearing, and the connecting rod doesn’t need a split bearing.
First, the connecting rod:
Completely machined the first side of the connecting rod. The two bores, and the contour are on finished size.
Next, I machined a set of soft jaws to hold the connecting rod, to machine the second side. (The jaws have been used before, hence the extra machined areas)
The second side is being machined and the finished rod, still in the vise.
Here we have all the parts for the assembly:
The needle bearing inner ring is the crank pin. The crank web faces are turned true after they are mounted to the shaft. The whole design relies on the faces to be very accurate, as even a small error would cause a wobbly crankshaft.
Test fitting of the crankshaft to show the inner ring installed.
Needle roller bearing is installed in the rod.
Connecting rod is installed on the crankshaft.
The piston is made out of cast iron. The rather large groove will be for the O-ring piston ring.
The entire assembly finished.