Brucey wrote:one of the things claimed by the manufacturers of such products is that (when applied in liquid form) the uncured threadlock provides a consistent kind of lubrication to the threads, so that the torque setting vs bolt tension isn't so variable as it might be otherwise.
However, on the minus side, many torque settings are specified dry, and the use of any lubricant can result in excess tension in the fastener.
Exactly the point, both torque values and rotational setting are rendered inaccurate by lubrication.
Loctite is a lubricant.
yes it is a lubricant, and in some cases torque vs fastener tension values are claimed to be more consistent
with it than without it. You can design and specify torque settings for lubricated bolts and in some cases this gives better results than if the same machine is specified for dry assembly (even with the appropriate torque settings).
Correctly torqued fasteners / fittings will not work loose.
that is only ever true given the caveats that I mentioned previously, and sometimes not even then; there are all kinds of machines that occasionally see vibration conditions that are very likely to loosen even correctly torqued bolts.
If you have to glue a fitting in place you need to review your procedures.
or it might have been designed to work best that way; very many modern machines are designed to use bonding agents on threaded as well as unthreaded assemblies, for cost, weight, performance, safety reasons.
It perhaps ought to be instinctively obvious that loosening of fasteners is a very commonplace (and thus most probably not invariably avoidable) occurrence; one only needs to look into a fastener catalogue to see all manner of devices that are intended to prevent fasteners from backing out/loosening/falling off. If there were no reason for them to exist I doubt there would be as many as there are, and if they could be avoided entirely then for cost reasons they would be, in all kinds of mass-produced machines.