How is the quality of cheese relevant to the sale of bagged milk?
We're talking about milk here, not milk products.
Oh, that's good to know. Thanks.
where you should be on related lifts
What does that mean? You are where you are. Where you should be is where you end up when you do your best. Knowing the absolute resistance on a machine doesn't help with that.
gauge your progress compared to others
If you mean comparing to other people, I strongly recommend against this. Compare against your past self, and only your past self.
Where can one learn this power?
How do you remember to go back to it if you don't keep it open?
~~Considering that it has to go through the belly button, I'd rather not, thanks.~~
This is apparently not the case anymore since the 1980s.
Curiosity would be the only valid reason for knowing. You can't compare between machines, even if they're the same model.
I was also using the (Cybex) overhead should press machine and saw that the plates past 50 pounds went in 15 pound increments. Then I noticed the additional weight at the top, disabled by a pin. When I lowered it down on to the stack there was no number on it. Was it 5 pounds? 7.5 pounds? 10 pounds? Who knows?
A trick for these machines if you want to add weight in smaller increments and also know the weight you're adding is to place a small plate on the pin (On the yellow pin in the image below). It would look something like the second image below. You can do that instead of using the unlabelled weight on the stack.
And as many others have already said, the actual number doesn't matter much. If you go from one machine to another, even if it's the same brand and same model, the same weight is going to give different resistances. The part that matters is that you progress. You know that if you add weight on the smith machine, then you're moving more weight and you're progressing. If you enable the small weight on the shoulder press machine's weight stack, then it's more weight than not having it enabled, but less than moving the pin down the stack.
OP is looking for the weight of the bar on a smith machine, which means they'll have to take the scale with them to the machine. That's definitely not going to fly in most gyms. Nor would it work on the weights on a machine's weight stack.
Depends on your gym layout I guess. I've done this a few times when the bar weight felt off at a new gym. Do what you need to do. Don't let the fear of weird looks deter you.
Nor are most people making cheese with bagged milk from the grocery stores.