How a turnbuckle works is to first unscrew the end fittings all the way out and take care not to screw them too far (inside the ends of the turnbuckle body）. Then attach each end of the turnbuckle to the work pieces. Be sure that the end fittings cannot turn.Then turn the turnbuckle body. One end fitting has left hand threads and the other has right hand threads.
If your application will expose the turnbuckle to vibration, it is good practice to lock the end fittings from turning by using lock wire.
This will prevent unwanted loosening over time. Your turnbuckle may also be equipped with lock jam nuts to prevent loosening.
Beside above, can turnbuckles be used for lifting? Rigging screws / turnbuckles are also used for lifting applications though before using to lift with please check with the operation and used manual to ensure that they are certified for lifting; the reason being that many manufacturers only certify for pulling applications.
Accordingly, how do you tighten metal cable?
How to Tighten a Steel Cable：
Unscrew the eyes on both end of the turnbuckle until they are as far apart as possible without falling out of the buckle.
Slide two cable clips onto one end of the steel cable.
Insert the cable through one eye of the turnbuckle.
Fold the cable back on itself and slide the cable clips over the tail.
How are turnbuckles measured?
Use a straight ruler to measure the length of the inside of the take-up. The take-up is what is turned to loosen or tighten the turnbuckle. The inside of the take-up is the rectangle inside the frame through which the threaded rods can be seen. Measure end to end of the inside of the frame.
