"I'd stay away from them as already mentioned for critical steering and suspension joints."
Good morning Grigg.
If I'm not mistaken they originated in aircraft applications and based on that the quality ones must be pretty robust as long as they are sized correctly for the application. The Speedway Motors catalog lists a variety of spherical rod ends. It's hard to imagine how there could be a problem if the SCTA required washers are used. If they're adequate for a 400+ MPH streamliner they must be pretty solid.
One of my sons is a mechanical engineer and he works in a test lab called Tension Member Testing. They test some really massive stuff there, stressing it to failure with fixtures that can apply in excess of a million pounds pounds of tension or compression. If anyone's interested I can ask him if they've tested spherical rod ends. The manufacturers of those parts have test data also that would give people a comfort level. Here's an example:
http://www.rbcbearings.com/literature/pdfs/rbc-heim-092109.pdf
Their offerings vary from miniature up to 1" shaft, with and without grease fittings.
But there are other options. When I restored my '36 PU it had clunky, loose, spring loaded tie rod ends on the tie rod and drag link. Digging through a Moog suspension parts catalog back in the 1970s turned up ES29R and ES29L tie rod ends that had the same internal threads and the same taper as the original parts without the complexity and looseness. Using them on the drag link did require getting a round bar and threading the ends with left and right hand threads for ease of length adjustment. That was a quick and easy lathe project. Those Moog tie rod ends are still tight today.
Chad may find an equally adaptable part for his application by doing some research. It's amazing what's out there.
