ORIGINAL: drac1
ORIGINAL: Truckracer
ORIGINAL: dirtybird
Engineering requirements require bolt depth to be equal to the width of the bolt. Any more is just a waste of the bolt.
I'll be sure to remember that the next time I see a steel bolt cleanly pull the threads out of aluminum.
Lets see, given your formula, a typical 5mm muffler bolt would have just over 4 threads holding into the aluminum cylinder. Is that really enough? I have rarely seen any engine or muffler supplied with bolts that had that little thread engagement and when I did thought it was an error on the vendor's part.
I'll leave it at that.
Dirtybird is correct. Maximum bolt holding strength is obtained when the bolt diameter = depth of thread. Measure the thickness of a 5mm nut and see what you get.
But that formula would apply to steel bolts and thread. I would think when using softer metals it would change. You would need more thread engagement.
Most times when a thread is stripped, it is because the bolt has been over tightened.
We're not talking about a steel bolt threading into a steel nut here. We're talking about a steel bolt threading into an aluminum, mystery alloy Chinese cylinder. I still maintain that I'll take advantage of all the threads I can. The engineers that insist on sticking with their text book theories can use 4 threads of engagement as they wish.