I've been sewing for over 40 years and have never knocked a machine out of time. A vintage all metal machine has to be really, really abused for that to happen. I sew over pins, forget to change my needle plate, you name it I've done it. Only once did I hurt a machine. When I got my Brother PE200 embroidery machine a couple years ago it had a class 66 bobbin in it. I knew that couldn't be right so I googled the machine and on three out of the top five sites that came up people said that it does take that bobbin. So I loaded a hoop and hit start. Stitch, stitch, thunk! and the needle bar popped loose. I fixed the needle bar and got the correct bobbins and it works like it should. I should've listened to my gut in the first place and asked at the Brother dealer BEFORE I ran the machine.
Cari