...would be different that preloading 3/8 studs right? I originally set the preload on my promags to 1/4 turn, then I started going to 1/2 turn...but it just occured to me that many people use 3/8 studs and they have a different thread pitch. Any preload specs for us guys using 7/16 studs? I'm used to setting preload at 1/2 turn with stock lifters, 1/4 turn with high energy lifters and zero with comp R's, but that's assuming a 3/8 stud.

 

I wrote that down somewhere after having the same question.
here. I found it.
3/8 stud has a fine thread, .020" per 1/2 turn
7/16" sud has a less fine thread, .030" per 1/2 turn.

Those are from my measurements with a ruler.

Does that jibe with other's measurements?

Karl Ellwein

 

3/8 fine pitch threads are 3/8-24 or 24 threads per inch(TPI). Each thread is then 1/24 or .04167 per turn or .0208 per 1/2 turn.

On most calculators, enter 24, then 'divide' then 'equals' to get the reciprocal (.041666...). If your calculator has a "1/x" button use that. Divide the answer by 2 to get the 1/2 turn, or divide it by 6 to get how much one flat of the nut moves the rocker.

7/16 fine pitch is 7/16-20 or 20 TPI. You can do the math.

FWIW, a micrometer (inch, not metric) has a very accurate 40 TPI thread. That's how it gives you measurements: .0250 per turn.

"Understanding how to get the answer is easier than memorizing the answer."

 

so the threads on the 7/16 studs aren't as fine by roughly 17 percent in other words. Meaning I would have to turn the polylock 17 percent less with 7/16 studs...

so I'm guessing I should take it down roughly about 1/10 turn less? Does that sound accurate?

 

Why complicate things unnecessarily. As recommended, do the math. 20 tpi is .050" a revolution. What are you after? .010"? .020"? That will determine the degree of wrench rotation.

 

Yes. pretty close I'd think.


Karl

 

LOL, this is a pretty funny thread. You guys realize you're talking about 1/10 of a turn? Id say setting them pretty much the same as the 3/8 stud preload is going to be close enough, unless you're building a top fuel dragster that is, which I know you're not.

 

I set my preload at 3/8 turn with 7/16 studs. So right between 1/4 and 1/2 turn. This is comparable to just a hair under 1/2 turn for 3/8" studs.

Dan

 

LOL, true, it is kinda funny...but I had a problem with guideplate wear not too long ago, and I couldn't figure out the problem, so it left me wondering if it had anything to do with the preloading of the rockers. Just wanna make sure it's done right.