I’ve got an Axminster 4″ MCB100A metal cutting bandsaw, and a wonderful bit of kit it is too! However the blade started coming off and it wasn’t obvious how to adjust it.
I took both of the wheels off – they just unbolt. The driven wheel isn’t adjustable, so it is important to ensure the back of the spigot is really clean so the wheel is correctly aligned.
The idler wheel is adjustable, but I didn’t realise this until I took it off. This is what it looks like:
The two grub screws sit on the marks on the aluminium casting between the springs. You can adjust them without removing the wheel through the two holes in the wheel, although you will need to slacken the centre fixing bolt first.
In my case I wanted the blade to sit slightly further back on the wheels, so I tightened both screws by about 1/4 turn. The blade now runs perfectly with no more jumping off.