sam lingo wrote:
>
> I've always wondered why drop outs were attached
> tongue in groove rather than by a lug (i.e., a stay
> inserted into a cylindrical end on a dropout). A lug
> would seem a stronger joint and, could likely be
> engineered and machined to be quite light. Fabrication
> seems technologically feasible. Assembly seems no more
> difficult, perhaps even easier. A lugged bike might
> look more unified (and beautiful) in appearance with
> matching lugs at the frame ends and frame joints,
> rather than tongue in groove at the frame ends and
> lugs at the frame joints? Perhaps the KOF frame
> builders could weigh in here and explain why tongue in
> groove is preferred. I assume it must be superior for
> some reason, or it would not be done, but I'd like to
> understand why?
Standard dropouts are simple forgings -- creating a socket would require casting, and that in turn can be complicated due to the number of different angles at which the stays can attach to the dropout.
Nagasawa and probably others used a two-piece casting to get a socketed dropout capable of accommodating a variety of stay angles:
http://www.os2.dhs.org/
But these didn't lend themselves well to mass-production.
--
John (john@os2.dhs.org)
Appleton WI USA