"...or Blindnietschraube..."
Yes, that's what I realized too late. I thought of a common type of Niet, which has no thread, so it threw me off.
"As for the length matching, this could be determined ahead of time, so I thought the emphasis was on screwing all the way..."
Technically, the German doesn't include "man," nor does the author use the imperative. It's a requirement. My next statement will sound weird, but I'll use your "spin on" and try to be as literal as possible (a bit shorter, though):
The sleeve must be capable of being spun on up to the entire length of the thread.
Little bit better:
It must be possible to insert the entire thread into the sleeve.
Just like the sentence that comes after this one, it's a statement of what must be possible, not one of what you must do. However, I don't know who wrote the document. I think we're missing a sentence.
Here, they use the imperative (which sounds better, IMO):
"Insert the rivet nut and tool into the drilled hole to the full depth of the rivet and try to keep it square-on to the surface of the sheet you are inserting it into."
http://www.crosab.com/uploads/product_info/KEN/569/KEN569308...Best wishes and good n8