30-03-17, 11:46 PM
I don’t believe it, you're talking like a prat, and what a load of bollocks.
No, hang on a minute, you're right.....
A dry surface between threads, or worse still a rusty surface gives a resistance to sideways pressure. So some torque is taken up just moving the nut sideways. What we are after is downwards pressure, and the thread is just the convenient way of providing this. So as loose and free running thread as possible means all of the resistance is being caused by upward back pressure, and that's what you're measuring.
Unless of course the manufacturer set the torque values compensating for dry threads.
That's my take on it anyway
Mtread - GCE 'O' level Physics 1971
No, hang on a minute, you're right.....
A dry surface between threads, or worse still a rusty surface gives a resistance to sideways pressure. So some torque is taken up just moving the nut sideways. What we are after is downwards pressure, and the thread is just the convenient way of providing this. So as loose and free running thread as possible means all of the resistance is being caused by upward back pressure, and that's what you're measuring.
Unless of course the manufacturer set the torque values compensating for dry threads.
That's my take on it anyway
Mtread - GCE 'O' level Physics 1971