Instruct: Classify a given review into positive or negative sentiment.
Query: Disks lasted less than two seconds

I bought this to cut some metal in very close quarters. Knowing that putting lateral pressure on the disks would probably destroy them, I worked very carefully trying to keep the disk exactly in the saw cut.However, the metal collar that the mandrel slips through kept tearing through the side of the disks rendering them useless. None of them lasted more than a few seconds. After that the metal collar was practically impossible to remove from the mandrel. This idea looked good on paper but at least the batch that I got was of very poor quality.What did work were the smaller fiberglass-reinforced Dremel cutoff wheels. No fancy mandrel or metal collar to rip out, but they got'er done.