Corroded studs. Wow!


(PeterCrespin) #21

The threads are cut, not rolled. Cheaper but not as strong AFAIK…

If both ends are shaped like the picture they are wrong. The block end should have a short thread-free section with a tapered pointed base to sit in the block hole and spread the load on tightening in the block


(Matt Furness) #22

Rolled threads have better fatigue resistance than cut threads…so will last for 1 million cycles under a set of loading conditions whereas the cut threads will only last 500,000 cycles under the same conditions …and the numbers are statistically based rather than hard numbers so there are confidence limits…" Stud will have a 2% chance of failure at 1 million cycles" type statements.
For a " low cycle" use there is no benefit.
Interesting challenge to get bolted connections right.


(69 FHC ) #23

Not doubting the accuracy of that statement but I’d be interested in knowing the “why” behind that.


(Matt Furness) #24

Because the thread form has a compressive layer on the surface because of the rolling…gotta head to work …but that is it in a nut shell!!!


(Paul Wigton) #25

Thar ya be!

http://www.atlanticfasteners.com/cut-vs-rolled-threads/


(69 FHC ) #26

That makes sense. Thanks.


(Paul) #27

Wow. Well done. Good for you, consider yourself very fortunate.
In my experience, honestly, I cannot think of many greater feelings of victory than the removal of corroded/seized studs or broken bolts!

I want to wear them around my neck like a bear’s claw or something.

Anyway, consider yourself lucky once again…zzzzzzzzz
Despite the outward appearance of an old jaguar stored many years, without a doubt the paramount concern…

@MGCJAG: Thanks for that! Great link. Will make note for next time.

PS.
The water pump interior and motor passageways appeared it came from titanic despite perfect exterior and even pump movement. Do a search on “welcome to hell” here.
Fortunately all cleaned up perfectly with no head or block damage of any sort other than slight corrosion at one water inlet port at head!
I was blown away and thankful beyond words.
Pump rebuilt by Welsh for $100…
Kind regards