Tractor Trailer Landing Gear Crank System

So, I need a little information about a project I am required to do.
Specifically, I need to know the measurements of the spigot that the actual crank handle attaches to on a tractor-trailer. (Now I don't know if that's the proper name of it, but that's what I'm going with.)



I am not sure if there's really a standard size for how big around it typically is, (1", 3/4", 1/2" etc) because there is absolutely 0 information on it. I'm not too worried about length because I've been able to find numbers for that and it seems like it ranges from around 4" - 6" (correct me if I am wrong).

Now if there is no standard size for how large around they should be, then just knowing the largest size that one will probably encounter would also be a big help.

Any type of help with this odd question would be extremely appreciated.

 

Thank you very much, you're a god-sent.