BB is 16mm Cranks are not?

[jimius]

So i have an old Peugeot racing bike I'm converting to a singlespeed. Getting the old cottered cranks off was a bit of a hassle but was managed just well.
Now I got a used cottered crank, but to my amazement, it doesn't fit. I found a newer one, and no fit. Went to the local biking shop where they had a cottered crankset i could have for cheap, and the fella ensured me it was 16mm because the 16mm BB he had there fitted smoothly over it.

But when I measure it with my sliding tool (i forgot the name) it's about 15.85, not 16mm. So it too won't fit.
Am I missing something here or is 16mm just an odd french measurement?

[RobAR]

Hi jimi. Read this... http://sheldonbrown.com/cotters.html ... was the answer there?
If not, I am stumped unless one of your parts are proprietary to a particular company. EXCEPT.. you don't say if you measured the OD of the axle or the inside dimension of the crankarm to get 15.85 on your calipers? A few more details and a pic of the whole bike (we're into bike pron), might help. Details like model, pic of headbadge, what stem, etc.

To the best of my knowledge, outside of rare proprietary parts (which Bianchi was not known to use, excluding Campagnolo), all cottered cranks and their parts are standard axle size. Here's the catch,,, does the arm slide onto the axle but not tighten with the pin? The pins come in two sizes to meet the Broach of the interface. 9 and 9.5 are pin sizes. A 9 will never tighten a pair broached oversize that require a 9.5

Am I on the right track?

If you have a Campagnolo (Campy)-equipped Bianchi from before 1990, you are doing the world a dis-favor by altering it. If that Bianchi is pre 1983. Shame on you BIG TIME. IMHO, of course.

[jimius]

Well, the OD of the axle is 16mm, the ID of the cranks I have vary from 15.7 to 15.85.
I'm not at home right now so I can't take pics at this moment. AFAIk the frame is a Peugeot with a steel frame with "carbolite 103" on it. Don't know the exact model#. I tried heating up the cranks but it won't fit that way either.

The arm does not slide over the axle. I now about the cotter pin size and have some 9,5s and 9s laying around and am not expecting a problem with those. But without the arm on the axle i won't even be able to get that far. It seems the axle size is too large, but I have no clue why.
Rally frames are supposed to have thicker axles, but hardly worth making it thicker with just 0.2mm. Also it's a slender racing frame, so I'm not expecting a rally BB on it. Since a double bladed crank came off it.

Afaik the frame is from the late 70s, I'm not too familiar with bicycling brands, i'm just learning as I go along. But any advice would be helpful.