Torque wrench...? I was taught that the size of bolt, the material used and the thread type, alongside the likely spanner weight and length averaged out one`s expectations on how much pressure to apply when tightening things....?
I read somewhere of a study that demonstrated that for fasteners tightened without a torque wrench, the vast majority of small sizes were over-tightened, and the vast majority of larger sizes were under-torqued.
I was amazed when I did the cambelt on my Ecotec engine. Because it has variable cam timing I decided to replace the cam wheels at the same time as they have internal oil ways and gubbins to do the phase change. There are no keyways or detents on the cam shafts, the wheels are just dialled into position and locked on to the taper with torque, about 95 ft-lb if memory serves. You certainly wouldn't want to get that wrong by under-tightening and having them come loose! :-)