Bolt Thread Hole Clearance

GoldenMotor.com

MEASURE TWICE

Well-Known Member
Jul 13, 2010
2,784
1,296
113
CA
I found this chart:


The thread clearance I saw for what I think is a 3/8" bolt, it shows Fit Class Normal, Close, & Loose.

It would be alright to have Close and it would be the 0.391" to 0.397", but if and only if the bolt is NOT part of a clamp that has moving parts with some play in lining up exactly.

I may just drill out a bit bigger clearance and not have the threads damaged by just using the clamp as is.

At first I noticed one of these clamps with a good size dent in the bolt's threads. I know that the bolt threads get messed up with every time it passes through the clamps threads, so that means better off trashing both parts. Replacement came with same clearance, the thread quality still not very good.

The clearance scraping along the bolt threads on the clamp may not distort both the threads if it is not clamped under load I know.

It is just that trash parts are like trash is as trash does.

Oh, and what does this all have to do with, but the camper shell clamps on my pickup truck.

Funny though, after the last steps in sealing water out, I noticed some water in very light rain that was not before I took a short trip to the dump/recycle in light rain. I did not only seal the shell, but also the fold down window in the shell adjacent to the cab.

Later I noticed that I had put a 32 gallon plastic trash can on it's side in the truck shell. I had forgotten that while I was cleaning up finishing the job of redoing the gasket seals, I had that very trash can not under my car port. I got some rain water in it along with a little trash I had put in it. I did not bother to drain the rain water out of the trash can.

With the trash can on it side the lid allowed a slow leak of the water. I saw that the water was not dripping from anywhere of where the bed rail new seal nor the fold down window seal were redone.

Seems it should be alright. If someone says parts are good and you just have to use a wrench to see if threads are good, I would have to say steer clear of them.
 
Last edited:
  • Like
Reactions: fasteddy