: What did you pay for the u-bolts and nuts?

As I recall, the U-bolts were less than $2 each at Ace Hardware - I didn't search for a deal, so there may well be better resources out there.

: One concern is that the setup would be very top-heavy. I imagine you anchored
: the beam to your sawhorses with another u-bolt.

The beam is u-bolted to the stands. I used homemade stands so that I could put them on casters - only partly successful with that part of the design. I also u-bolted a 2x4 under the beam at the mid point, and then used 12" pieces of MDF to form a table. I'll have to redesign when I flip the project for the deck, but I've come to really appreciate the table surface.