My longarm would go right over a 1/4” ruler and would be a terrible thing- for the machine and probably for me. All of the longarm rulers I have purchased were just a hair under 1/2” thick. I’ve only purchased longarm rulers from HandiQuilter since my machine is a HandiQuilter Avante. I get a good deal. I tried my ( cutting ruler) once when I first tried ruler work. It was a disaster. Broke my needle, knocked the timing out of whack and bruised my finger. Learned my ( costly) lesson.