A good while back I picked up three packs of ten cheapo bubble levels from eBay, just out of curiosity. From China of course. Ten tiny ones (7mm diameter), ten slightly larger (12mm) and ten "large" ones (32mm), all of the circular disc type, the large ones with several lines purporting to show degrees.
I tested them all against a calibrated spirit level I borrowed from a friend and the results were not great. Of the 7mm ones I kept 3, of the 12mm ones I kept 4 and of the 32mm ones I also kept 3. The remainder all had serious deviations and ended up in the garbage.
Just a FYI in case anyone has bought, or are considering buying the same. By all means do so, but don’t take their accuracy for granted and don’t rely on them before you’ve checked them against a verified spirit level.
I tested them all against a calibrated spirit level I borrowed from a friend and the results were not great. Of the 7mm ones I kept 3, of the 12mm ones I kept 4 and of the 32mm ones I also kept 3. The remainder all had serious deviations and ended up in the garbage.
Just a FYI in case anyone has bought, or are considering buying the same. By all means do so, but don’t take their accuracy for granted and don’t rely on them before you’ve checked them against a verified spirit level.