My first rod I cut "V"s in a box, put the spool of thread in a cup, ran the thread thru a book.
I later bought a cheapy rod wrapper from Cabela's. It had a spring loaded tensioner but as the spool turned the nuts holding the tension would unscrew, a worthless POS IMO.
I bought a thread tensioner from a sewing machine parts company but never figgered out how it worked.
Went back to the cup and book (I use a Websters Dictionary with the thread running thru at about the D section).
I have wrapped over a dz rods with that method....works for me.