I've got two extras at home, will post photos later to verify they are correct. Came with some other parts. Maybe yours can be repaired also, others will chime in I'm sure.
Here's some pics of steering box end plate and tube. My 39 pickup had a brass tube attached to plate and I did have to repair it because it was cracked at plate. The extras I have are different with a steel tube and seem to be smaller in diameter than the brass one if my memory is correct. Hope someone can confirm a change occurred when the horn rod was eliminated as the extras were with a steering box marked 41 Mercury.