I'm installing a suspended lighting track system in a concrete ceiling. The ceiling has some abnormalities and the anchors (seen here: https://www.grainger.com/product/DEWALT-ENGINEERED-BY-POWERS-Vertical-Rod-Hanger-Anchor-54PD63) I've installed are slightly off so that when I insert a 5 foot 1/4 20 threaded rod, they all hang un-level (there are about 16 of them in total). I know that I can bend the rods to appear level - but I thought a better solution would be to purchase these from mcmaster carr:
This pivot adapter can screw directly into those ceiling anchors.
The problem now is that the set screw cavity (which the threaded rods will go into) is 0.328 or 21/64"
I can't find a M 0.328 to F 0.25 adapter.
Any ideas on how to do this? Should I just use a hand-tap to make that hole 3/8 so that I could more easily find a 3/8 to 1/4 adapter? Is there some kind of sleeve I can insert to accept the 1/4" threaded rod.
Per the answers below, I just want to clarify that I am using the set screw threading to insert a 1/4" threaded rod. The hole is too big and I can't find an adapter suitable. Thanks!
****Ended up just ordering threaded rods @ 5/16 24 which fits perfectly in the coupling. The 15 degrees from center of movement is perfectly fine because the threaded rods are 5 feet long. Did a strength test too and the couplings are more than suitable to support the lighting track. Thanks everyone for your help in troubleshooting.