What is a ” lockout” spring and brake stringing machine?
A machine with a spring and brake tensioner relies on a hand operated crank to pull the string. A spring deflects against the tension being applied to the string. When the pre-selected tension is reached, a lever is tripped stopping the tensioning operation, and a brake is engaged to hold the tension in the string for this reason, these tensioners are known as “lockout” or “instant off” machines. When properly calibrated, spring and brake tensioners are very accurate and allow fast stringing, which is why they are extremely popular in pro shops. Because these machines “lockout” as soon as they reach the reference tension, professional stringers usually set the tension about 10% higher than they do with “constant pull” machines (see FAQ 11 for an explanation of the difference between instant off and constant pull machines).
