Amid other chores and responsibilities I worked on the oil cooler hose adapter. I had the adapters for the four inch and three inch hoses and then made a plate to go inbetween the two for riveting the two parts together.
I completed the 3 inch shallow counterbore in the plate that would easily locate the adapter centrally on the plate and drilled the six holes in the plate and match drilled them into the 3 inch adapter. I then located the 4 inch ring concentric with the outside of the plate and clamped it and match drilled the holes already in the 4 inch adapter I bought from Vans.
I removed the parts and deburred. Just have to countersink the holes and rivet with flush rivets.