I gave up on the idea of using the 1/2" steel rod for a drive square. A smart guy on my ST forum pointed out that that piece would probably twist under big torque loads.....sounded reasonable to me.
I decided to go with this plan:
http://www.freeinfostuff.com/TorqueExtension/TorqueExtension.htmThanks, Verslagen, for turning me on to that web site!
I like how it ended up (I painted it gold because that was the only can of RUST-OLEUM I had at the house):
Jerry, the owner of Hinrichsen & Son Welding (near Circle and Platte in Colorado Springs) did a very nice job with the welding and his cost was certainly fair. I would recommend him to anyone in this area who has small jobs to do....he welcomes small jobs and is an interesting fella to talk to.
A look at both sides of each end:
As you can see, the welds are stout.
All told, I've got twenty bucks tied up in this 1/2" drive torque extender, including the gold paint. It measures about 13 15/32" center to center between the drives. It turns my 0-150 ft-lb torque wrench into a
0-270 ft-lb torque wrench.
I'm pleased.
Thanks all, for your help and ideas!