[Formulajones]

Originally Posted by Greg Reid

I'm totally familiar with setting preload one half turn, one full turn, etc. from zero lash but how do you measure preload in thousandths of an inch as some of you have mentioned? .050" for instance.

Threads per inch of the stud you're using. Doing the math will give you a specific amount of movement based on the rotation of the nut.

For instance a common 7/16-20 stud used today, every full turn of the nut moves .050"

In most cases that's close enough for government work but for those that want to get picky you can get into rocker arm ratios that will change the amount of preload on the plunger depending on the ratio of the rocker arm.

With all that said, easiest way I've found is to just set up my dial indicator, get to zero lash and just measure the preload on the plunger at the pushrod/rocker............done.
Then you can forget all about what stud or rocker you have and skip the math equations.