I've since beefed it up.
The whole receiver was bolted onto the front side of the F150 frame flange.
I made it mainly to move empty trailers and hold stuff like a lumber rack.
Then wouldn't you know it I had to maneuver a heavy one.
I knew that day was coming and it came.
Had to horse a
5,000 lb boom lift around and it was visibly flexing.
I had to push the boom lift over very uneven ground over tree-roots etc, in granny & 4wd & locked up!
I kinda knew it needed an a brace on the backside for any weight on the receiver, but didn't wanna build it at the time.
Nows the time.
Here's the back-side brace, looking down, from behind the grille.
To the right -----> is forward.
That's 1.5" square tubing with .25 thick walls.
Those tabs are all 3/8" thick.
This basically braces the inside of the front frame flange.
The hitch is bolted to the outside (front) of this frame flange.
I attached it to the truck frame with this 3/4" all-thread rod.
There was a hole thru the frame box section with appx. 7/8" holes
Note the "shoulder-nuts" that I made with the angle grinder.
These engage existing Ford holes in the F-150 frame.
It's firkin' solid now!
But..... I have never had to push any real weight around since.