Here’s the modified steering column and Lifeline weld-on boss all machined and ready to be welded up:
The top hat acts as the bearing carrier for a roller bearing that supports the column inside an outer tube. It needs to be removable to replace the bearing and will be held in place with a roll pin. The weld-on Lifeline steering wheel boss and column are also drilled through so will be mechanically joined as well as welded.