I'm not a hundred percent sure but I think I may of held the sander at a bit of an angle and it also may of got caught on the edge of the timber. But new belts aren't to expensive and rather easy to replace. Thanks for watching.
By the way you're standing, the poor performance of the belts and your panting and puffing you're pressing down way too hard. You don't need much down pressure at all. If you lean on the matching then you drive the grit too far into the wood, which causes the belt adhesive to rub and heat up and the belt then to break. It also means you're going to have to fight with the machine more and increases the likelihood of it shooting off into a wall and damaging you, it, or whoever or whatever is in its path.
