Two holes to be drilled and tapped M1.6 in the bottom of each conrod and then the shells have to be made. Like the small ends, the big end shells are made from Phosphor Bronze. Two flat pieces are soft soldered together, held in a four jaw chuck and drilled (under size at this stage) on the joint. Then the outside diameter is turned to size and parted off. Warm gently to melt the solder and split the shells. Fit them in the big ends and tighten with the M1.6 screws, then set up on the mill and bore the big ends to size. Job done. Then its a matter of fitting it all together and seeing if the engine runs.
To give you an idea of the size, the distance between centres is 29.0mm.