Swiss BB tap in PDX?

[Dave Feldman]

I have been contacted by the owner of a Motobecane that needs it's Swiss BB  threads chased.  Does anyone between Salem and Seattle have a left hand 35 x 1 bottom bracket tap?

David Feldman 

Vancouver WA

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David Feldman

Vancouver, WA

[Mark Bulgier]

I have Swiss taps in Seattle but I don't lend them out, sorry.  I can do the chasing if you can get the frame to me.  

Mine are Hozan and not piloted, so shouldn't be counted on to improve the concentricity, they'll just follow the existing thread (realistically, mostly the first one or two threads).  I could tap the left side with my piloted Campy French tap, and just use the Hozan on the right.   

I know with shipping (or driving?) the frame round trip, plus my sub-par tap, this isn't a very attractive offer.  But I searched for that tap for years before I found one, and I don't know how hard it is = how many frames I can tap with it before it gets dull.  So I need to get paid.  Let's say $50.

Or, as I did for another guy once, I can ream the right and tap to Italian, with a piloted reamer and tap, for weird hybrid threading but nice and precise.   Then if you'd rather have English threads, you can get the Italian-to-English thread adapters that Ceeway sells.  If you don't know them, they're super cool, with a right-hand Ital thread on the outside and a left-hand Eng on the inside.  (How they manage to machine those, I can't imagine.)  There's no Ital-to-Swiss adapter though, so with either of those last two alternatives, he'll have to get at least one new cup if not both.

I hope you find another better deal, honestly!  I'm not looking for this kind of work especially. 

Mark B

[D Gillies]

Why would a Motobecane have Swiss threads?

- Don

[Mark Bulgier]

Don Gillies wrote "Why would a Motobecane have Swiss threads?"

You'd have to ask them, but many of them did. Sorry, I don't remember what models/years.

Why?  Possibly because it's the most logical of all the threading standards, the only one to combine the proven advantage of a LH thread on the right with a Metric thread.

Mark B in Seattle

[riendeau...@gmail.com]

In about 1974 or 1975 Motobecane used Swiss threads.  There was debate going on at the ISO meetings which were trying to standardized threads and sizes internationally.  For a time it seemed that Swiss threading might be the solution.   Soon, however, the might of the British, American and Japanese pushed the bottom bracket standard to BSC (1.37 x 24 tpi if I remember correctly).  In the same time frame 25.4 was supposed to be the international handlebar clamp standard, but the popularity of TTT created a de facto second standard at 26.0.  Nitto stuck to 25.4 on high end stuff.  There are Fred DeLong authored articles out there about the process- first in Bicycling then in Bicycle Guide.