I've got a 1916-23 kerosene tail light without the lens. I thought I was lucky when I found a lens at a swap meet, but when I got home it turned out to be too big for my rim..
The lens I found was almost 4" in diameter while the rim can take about a 3.72" diameter lens.
Were all tail light lenses on Fords about the same diameter during 1915-23 or were there differences between suppliers of kerosene lights?
I suppose it is an off brand lens I've found?
The lens isn't supposed to pass completely through the door. The lens should stop at that first step to the inside of your caliper jaws.
Correct. The measurements above are comparable. The lens opening in the rim is about 3.55" while the step on the lens where the rim opening should seat is about 3.75" in diameter. The lens is about 0.20" too large however I measure so it's unlikely it has anything to do with Ford, just wanted to check..