Amazon had a good deal:
Level-It - 1-7/8" Diameter Level Mount with 1/2-13 Threaded Stem
https://www.amazon.com/dp/B0029MRUKK..._YOfqzbT35YM8F
Local stores only had 3/8 and smaller, which might have worked, but I didn't want to be weight limited to how much of the car I could assembled on the table.
David