Bicycle Mechanics - Another question 'bout crankset compatanility.

I'm in the process of building up an old 57 cm Sekine Medialle frame (whys it always spelled Medaille?). I'm not sure what year tis. 70's. I plan to replace both the bottom bracket and the crankset.

First, how can I tell if I have ISO, JIS or other bottom bracket. Must I measure the shell?

Second, I am looking at buying a Sugino crank with 1/8" chainring for use with 103mm square taper BB.

Is it possible to find a new BB that'll fit this crank?

Last, I want to run a 7/8 spd cassette. Will I have any problems with the chainline running smoothly?

Thanks for anything :)

Oh. I've also been scouring the web for a new thumbie shifter - the lever type that mount right to the handlebars. Anyone seen anything like this?

Too many questions, but taking them in order.

Measurement is the best way to know, but you can also make an excellent qualified guess by looking at the right side thread. There are only two likely possibilities. If it has a left thread on the right, it's almost certainly British (now ISO, JIS is the same too). If it has a right thread, it's Italian. this isn't 100% certain, but the likelihood of Swiss or French threads is too low to worry about.

You cannot use a 1/8" chainring with a derailleur and cassette. That requires a 3/32" chainring.

Yes, there are 103mm BBs out there, you just need to shop for them.

I can't predict the chainline, you'll have to read the info that came with the crank. Usually if you use the specified spindle length you get acceptable chainline. But don't forget that you need to switch chainrings in any case.

One other note, and please don't get offended. Mix and matching components creatively is perfectly fine if you know what you're doing. But if you don't, it's best to stay on well trod paths.

ya sorry. coulda broken that down.

but that was extremely helpful! thank you. and non offense taken. i've built bikes before but never had to replace a crankset.

much appreciated.

Rivendell sells both cheap (falcon) and expensive (paul's) thumb shifters. Velo Orange has some sometimes too. I used one of the cheap rivendell ones and it works well on my 1x9 utility bike.