83 johnson 140

[tblshur]

why are torque values always like 20 to 30 ft lbs and not 20 or 30 ft lbs thanks for your help?:joyous:

 

[racerone]

?????-----That is fairly simple.---A torque wrench reads" the resistance to turning " and not an exact direct torque measurement--------Plus any tool like that may have some error.---So if the threads are not perfect / clean the torque wrench might read 3 ft-lbs resistance from turning which is not compressing the gasket and putting the bolt in tension.---There are other ways to put bolts in tension using heat / ultrasonics / length measurement.--------EG on Rolls Royce they say things like 65 FT-LBS / 0.002" stretch preferred.---And I have attended a seminar on bolt torquing tecniques !

 

[racerone]

I have witnessed ultrasonics used to torque fasteners.-------But you can use ---- " google " along with -----ultrasonic torque measurement --------to get the finer details of technology as used in industry !