(Posted this question on another forum first, but they didn't know for sure, so I'm trying here.)

Background: I've been cutting down 105mm microfiche for some antique cameras that are in my collection. I recently acquired a Seneca 3A Box Scout. Someone had helpfully (?) painted on the bottom in silver "Use 122 Film". I tried a roll, but it's too narrow and falls into the film gate, also leaving part of the red window uncovered. (Not really a problem with slow ortho film, but still.) I have since found online an old Seneca catalog which listed this camera as using 125 film, which has the same image size as 122 but a longer spool. Seems that box cameras of a given image size used wider film than folders of the same image size, so 124 and 125 were the box-camera equivalent of 118 and 122 respectively.

So I looked up the spool sizes. There's one source which gives the actual length, which is claimed to be 3.992". Every other source on the net seems to be copied from this one (including the table on pikiwedia's Film Format page; I know this because I was the one who added it).

Using this datum, I made a pair of spools. This was simple enough to do: saw a 122 or 118 metal spool in half (I've got a couple extra of these), cut a piece of 7/16" dowel to the right length, cut a slot in it the long way with a slotting saw, drilled round holes at each end, filed a key slot over one of the holes, slide it into the core of the two halves of the cut spool, double-check the length and alignment, and glue it in place. I checked the length with a dial caliper, and it's exactly 3.992 just like the table says. Unfortunately, this turns out to be too long. Can't close the camera body with the spools in place, and the paper which I cut exactly to fit the spools is too wide for the film gate.

I took the dial caliper and measured the width between the rails where the film/paper has to go. I measured it at 3.912", not 3.992". Looked at the list, and that's exactly the length of a 103 spool . . .

So my question is, does anyone actually have a 125 spool that they can measure? Or is everyone who publishes these lists simply copying data which may have been entered incorrectly in the first place? Am I really the first person since 1985 to actually try to make and use 125 film? And most importantly, did 125 and 103 share a spool, like 122 and 124 do?

(I've got a 103 spool coming from eBuy, hopefully to deliver tomorrow, so I can check if it fits. If so, I can just use that size, but I'd like to know if it's correct first, just in case I ever have to make it for someone else who has a real 125 spool...)