Help! I've been helping someone who has dug out an old Jones 451 sewing machine. We've got it threaded and going
. In the days between seeing it for the first time last week to now it has changed from straight stitch to zig zag. There is a button with M and a couple of zig zag/button hole options. It's on M but sewing zig zag. Does anyone have any experience of this machine and can point me in the right direction? I don't have the machine here so will have to relay any suggestions to the owner.