The three main blocks; the engine mount & the two fan shaft bearing blocks are all the same width. All three main shaft holes are aligned bored in these blocks at the same time. The fan shaft bearing holes are also bored at the same time. These three blocks & the main shaft are set up on a surface plate to ensure alignment. After alignment the three blocks are locked into position while still on the surface plate. Notice the split in the engine mount block that allows it to be clamped to the main shaft. The fan shaft bearing blocks are clamped in the same manner. All blocks have jack screws to make positioning on the main shaft easy.
