The art of imprecise or approximate engineering

[simmitc]

Over the years, I have fitted quite a few sets of taper roller wheel bearings. The relevant manuals have always provided a pre-load torque, a final or running torque and a back-off measurement for the securing nut (eg one flange and align hole for cotter pin, move cap for best fit for pin, or whatever; plus "x" mm play at wheel rim).

I have a small goods or box trailer and two dinghy trailers that, as luck would have it, all had rough bearings at the same time. Whilst the manufacturers were different, all three used the same bearing set. When seeking advice on the correct settings for bearing installation, the only information that I could obtain was: Do up the nut, but not too tight, then back it off a bit and fit the pin. There should be some play in the wheel. I wonder whether whoever produced that guidance would be happy if their payroll team worked to similar guidelines?

[islecastle]

Hard to tell if you are deprecating or praising fitting taper bearings by feel.
I've been adjusting taper bearings by feel for 60 years and haven't had a failure.
Maybe modern taper bearings are different to the old ones?

[les]

In my experience, I’ve nipped up the nut, (usually castellated) gently, backed off to the nearest split pin hole, insert pin. It does seem to be a ‘feel’ sort of thing.

[moggiethouable]

I recall adjusting taper rollers on a spitfire I owned.
The joy in replacing them as I recall was no power or pullers required to remove the old bearings.
The split pin holding them in could only be fitted in certain positions, inevitably.
This meant a small amount of play, but nothing untoward.
My opinion is in that case was the cum see cum sah fitment was beneficial.