Companies like Carrillo also prefer to use torque angle. It’s a good way of being sure about the stretch.
Modern OEMs are far more scientific in arriving at torque settings than your Ford story Mike (although a can easily believe that story is at least partly true). And the science is aimed at understanding the required stretch to achieve the required clamping force. They then work backwards from this to establish the torque required to achieve that stretch.
At an OEM we had to fit ‘trial’ bolts with mirror polished ends and heads, they were mirror polished so they could be measured for stretch in situ by ultra sonic waves. That info was then used to verify / establish the required torque. All very clever stuff.
But, IMHO Norton et al would not have employed anything like that! I assume they would simply have used standard tables based on diameters, materials, thread type, etc. And perhaps some trial and error.
Also, the dry vs lubricated issue is a bit more complex than many might imagine. Basically, unless you scrupulously clean both male and female threads with solvent, most fasteners are likely to have some oil of some kind on them. This also applies to Loctite, in its wet state it acts as a thread lubricant to a degree, not as much as the proper lube, but much more than a dry thread. So, basically, if you really want to be that accurate, you either need to properly dry, or properly lubricate, cos anything else leaves you in a large grey area and quite frankly, your actual applied torque could be miles away from what you set the wrench to.
And talking of the wrench setting… we have the whole topic of accuracy of different torque wrenches, there’s no way a given setting on a £20 Chinese piece of crap is gonna be the same as a £200-£300 Snap On!
Then there’s the topic of calibration. OEMs usually calibrate weekly or monthly usually (although they’re used much more obviously) and they do need surprisingly frequent adjustment to stay accurate.
Honestly, the more you look into this topic the more complicated it gets. But realistically we easily get into the realms that are irrelevant for our antiquated clunkers.
So, far from being a gorilla, it’s this kind of background which makes me rely on ‘feel’ where possible or appropriate, cos to use a torque wrench properly requires quite a bit more than simply yanking on some random wrench till it goes “click”.
