A tensioner works as it has a right handed thread and the opposite end a left handed thread. Tension can be adjusted by rotating the central body, this causes both ends to be screwed in or out simultaneously.
As a rule we always recommend to double the size of your turnbuckle from your wire diameter... eg. 3mm diameter steel wire rope we would recommend to use a 6mm diameter turnbuckle
What is the thread pitch are the rigging screws / turn buckles?
All of our Turn Buckles, Straining Screws and Rigging Screws are supplied with a Metric Coarse thread as per ISO 262 or BS 3643 specifications, please refer to the table below for thread pitches