Jerry Darnell has excellent videos on making strap hinges and pintles.He upsets the end on an angle of about 60 degrees then turns it over on the edge of the anvil right behind the upset then puts 2 vees in the stock.Then he puts the vees on the horn and hammers it concave,this is where the round stock is wrapped.The upset part has the material to fill the void.Weld together,take another welding heat and weld the bottom while in the vice.Another welding heat and using a header flatten where the hinge will sit,draw out the point.I hope I have explained it for others to understand,I got the video from Centaur Forge.The pintles end up looking like they were made from one piece.