How do you install the connectors for square tubes?

So I got those square tubing nuts from mcmaster. See this post for details:
https://tvwbb.com/showthread.php?75...nectors-Rusted&p=827994&viewfull=1#post827994

So how do you actually install them? Do you just push them into the tube and then attach the bolt to it? Or do you put it at the end of the bolt and then slide it into the square tubing?

I read in another thread that someone says I should use some grease.

I also wonder how do these round things actually grip the walls of the tube and not come out? Does it expand as you tighten the bolt?

Bill,
Just drive 'em in till they sit flush with the tube. I don't use grease for my installs but I do now use Fluid Film where rust might form.
They are held in from pressure from the spring steel not the bolt itself.
Jeff

i usually place a scrap piece of wood on the ground, slide in the threaded insert into the tube by hand as far as it will go (which isn't far, just enough so that it stays still), flip the tube upside down so the insert is facing the ground, and then hit the tube against the wood. 2-3 hits usually do the job.

....this is not rocket science. good luck

Oh, ok. I understand. I thought that maybe the insert had to go an inch (recessed) into the tube. Just making it flush is simple. Thanks!