I never thought about collecting them I use them!!!
learned on an inside read rule.
Couple of years ago the wife was yard saling and calls me what are those stick rules you love?
Inside read rules that is what they are they have almost a box full of new old stock for 2$ each do you want a couple? No buy them all!
So I oiled them and use them have them spread around the farm so I can find one easier! I don't wear bib overalls anymore so I don't have one in my pocket at all times.
I you can guess what the blue anodized aluminum guide is for I would be happy!