very long post. Sorry…
Two answers to different posts:-
Blade pitch:- There should be a minimum of three teeth in the cut and as few more as possible. Anything less than a 10/14 variable pitch is only really useful for cutting thin tube. That pitch will do for the thin stuff if you have a very light feed on the 4"x6" saws or a slow hydraulic feed on the 7"x12" saws. I tend to use an 8/12tpi blade for most work and a 6/10tpi blade when cutting more than 3". Obviously, most of the time I use whichever blade I put on last if it's just a single cut, because even a slow cut can be quicker than changing the blade
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Tracking:- It doesn't hurt to clean the wheels, guides, guards, etc every time you change the blade. Woodspoiling bandsaws usually have soft/rubber/polyurethane wheels because they get used with narrower blades that end up with the teeth riding on the wheel. A hard wheel would destroy the set of the blades in short order. Horizontal metal cutting bandsaws don't get abused into cutting circles, jigsaw pieces etc. so they can use blades of the same, larger, width all the time. A metal wheel lasts far better, especially if any coolant is used. Once the tracking has been adjusted so the blade runs lightly against the flange of the driving wheel, the next adjustment is the roller guides.
On the 4"x6" saws, with a single bearing on each side, adjust the guides so they're tight, less a smidge. You need enough clearance so that the weld can get through, any trapped swarf won't stall the blade in the guide and the bearings will last for at least a few blades. For the 7"x12" saws with two bearings side by side in the guides, it's simpler. Adjust the guides so that one bearing of each pair is firmly gripping the blade and the other one can be stopped by firm finger pressure. That'll give you good guidance of the blade without overloading the bearings.
The last adjustment is the blade tension. A saw with any pretensions to industrial use, will have a tension gauge, but the 4"x6" and 7"x12" saws we folks use don't tend to have that. For our saws, the correct blade tension is approximately "As tight as you can get it with one hand on the knob. Trying quite hard really!). after setting the tension, run it some more with the cover open, because the frame will probably have bowed a bit. Once you've got it running cleanly at this tension, it's unlikely to slip off the driving wheel unless you've managed to stall the blade, and that's less likely with the correct tension.
As for coolant choice, because my saw can go for a while without use and because I use it on my lathes, I use ISO46 cutting oil in the 7"x12" bandsaw. I only use it when cutting more than 1" section steel. Everything else gets cut dry. The soluble coolant I use on the surface grinder is enough of a hassle on that machine and I don't want two sets of tanks to worry about rancid coolant in. To be honest, once I've got the permanent airline and compressor setup I hope to install next year, I'll convert the bandsaw to a minimum coolant/mist setup.