Fittings

[philliosmaximus]

Bought a load of new drop forged doubles all kite marked ,
And the lads have said that that do up ok but are a nightmare to undo ,
And they have brought me 3 of these doubles that have tightened up so much they have sheared the bolts getting them undone,
These doubles look fine and are galvanised , so I was wondering if they just need a service or if the galvanising somehow heatens up or are they actually not fit for purpose , I have used a few and they do seem to tighten up quickly .

 

[aom]

I reckon it's just something that we are going to have to get used to as the manufacturer's try and cut even more corners.

 

[Alan Reade]

Getting Old Phil?
It may be a chemical reaction but have no real clue. I only found out recently that when you use stainless nuts and bolts they fuse when done up and cannot be undone WTF is that about?? could be something similar.

Test the parts with a magnet see if they are stainless?

regards
Alan

 

[TG6]

With fresh galvanized threaded components which have not been passivated properly, any water getting into the thread will form zinc hydroxide (white rust) which, at its worst will bond the nut onto the thread.
So - make sure that passivation has been specified.

Then don't put the nut/thread under stress, allow the white rust to form by keeping the fittings in a damp atmosphere for a while and run the nuts to clear the rust before using them, or:

use a water repelling coating on the threads, making sure that the full length is covered, especially where the nut will be when the fitting is tightened onto a tube.