I have bought a small Angle Grinder to do a couple of jobs. The cutting discs I have purchased are 115 x 1.0 x 22. When attached there is play and the Disc is wobbly. The Instruction manual does not say anything about Disc size but I know 115mm is correct and 22mm bore is correct but I was wondering if I should have bought Thicker ones, ie 2mm? Is that my problem as I cannot see how I could have attached the Disc incorrectly.