On 3/9/2018 8:52 AM, AMuzi wrote:
On 3/9/2018 12:54 AM, Emanuel Berg wrote:
AMuzi wrote:

Aluminum is no good for a bike frame because
it's too harsh and stiff. Aluminum won't work
either because it's too soft and noodly.
That went on just forever with, as always,
much digression.

One on-topic question on aluminium/aluminum
I thought about asking is how do they cut the
pipes so to get those roundish forms so that
for example the top and down tube aligns so
well with the head tube?


What do you have handy?
A milling machine is fast if you're making a lot of miters but a file
works just fine for one:

http://www.yellowjersey.org/photosfromthepast/MAK8B.JPG

IIRC, Cannondale pioneered using CNC to cut the miters with added tabs,
slots, etc. to allow more precise alignment prior to welding. That
doesn't matter for Emanuel's projects, though.

Maybe someday he'll want to splurge on a full set of frame building
fixtures like these:

http://www.henryjames.com/bicyle-par...equipment.html

http://www.alexmeade.com/Tools.htm

BTW, lots of people call those "jigs" but industrial tool designers
would call them "fixtures." The word "jig" is supposed to apply to
things that physically guide the cutting tool, not just hold parts in
position.

OK, that's enough pedantry for today.


--
- Frank Krygowski