Thanks Crashby! I figured they were probably 1/8", but you know about "assumption" being the mother of all f@#*-ups", right?
The Lunsford pieces aren't really all that much more expensive either. The steel Parma axles (which are probably great too!) are listed at $9 while the Lunsford pieces are $10.50. I'll probably go with the Lunsford parts since I've had such great luck with their turnbuckles for years.
Best,
Scottrik