This is a model of a steam turbine notch or closure bucket assembly. The buckets (or turbine blades) are inserted into the notch and slide into their position. This is generally referred to as a tangential entry design. The last bucket needs to be pinned to its neighbors to hold it in place.

This model uses a 3/16 pin to hold the notch bucket in place.

The correct orientation in the CAD image. The blue bucket is the “NormalBucket v1”, the red buckets are the “NotchBucket_NeighborBucketLeft v1” and “NotchBucket_NeighborBucketRight v1” and the orange bucket is the “NotchBucket_Bucket v0”.