What about Laser-cutting sheet metal (e. g. 3 mm) and have fingers and slots
for the metal tubes.
Once in place the tubes can be brazed on.
This is often used to connect dropouts to forks and rear triangles on stell
frame bikes:
https://meriwethercycles.wordpress.com/2011/04/19/brazing-the-dropouts/
Laser-cutting has become quite cheap and you only need 2D data.
Just an idea…
But what would you use as frame material?
a) thin-walled CrMo tubing (preferred, but expensive and harder to source)
b) V2A stainless tubes (nice, but soft)
c) cheap carbon steel?
Cheers, Christian
Am 23.10.2018 um 09:06 schrieb Jürgen Mages <jmages@xxxxxx>:
Agreed - I think, this is the way to go.
Just a reminder that there is a page in our wiki dedicated to collect
corresponding ideas and infos and everyone is invited to contribute:
http://en.openbike.org/wiki/3D-Printing_and_CNC-Milling ;
<http://en.openbike.org/wiki/3D-Printing_and_CNC-Milling>
People should be enabled to build their bikes without the hassle of heavy
engineering, special skills and expensive tools. I hope to have more time in
winter to push this development.
Imagine we could develop a scalable spaceframe model, where the user
specifies his geometric requirements and everything else is calculated
automatically ... He then only has to cut the tubes, 3d-print the
connections, assemble the frame and fix the nodes.
Regards,
Jürgen.
On 23.10.2018 07:59, Christian Winkgen wrote:
Just seen it - awesome!
I wonder how it feels riding it. Can imagine there is still a bit
flexibility in the frame - but who knows?
The wheelbase is quite short and the seat high. So it’s supposed to be agile
and turning quickly but still easy to ride because of the high COG?
What about doing something similar / parametric using rod end bearings and
lightweight steel tubes - like the front suspensions on formula racecars?
With the threaded end you can still fine-tune the geometry or just replace a
part with a short or longer version if needed.
There was a rumored development of a Moulton spaceframe „MDev 90" version
with carbon tubes being pulled together by tensioned wire running inside
(somehow like a spoke):
https://www.moultonbuzz.com/models/mdev-90/ ;
<https://www.moultonbuzz.com/models/mdev-90/>
https://www.flickr.com/photos/moultonbuzz/4508229953/in/photostream/lightbox/
<https://www.flickr.com/photos/moultonbuzz/4508229953/in/photostream/lightbox/>
Even this kind of frame could have been scaled easily by changing the tube
sizes.
Cheers, Christian
Am 22.10.2018 um 21:50 schrieb Jürgen Mages <jmages@xxxxxx
<mailto:jmages@xxxxxx>>:
Anyone remembers the picture of that prototype some years ago? I found it
amazing but there was no additional info and nobody thought it could work
...
Well now here is finally a project page with some videos and specs:
https://dbrcracing.wordpress.com/2018/06/17/pvc-and-duct-tape-python-low-rider-recumbent/
<https://dbrcracing.wordpress.com/2018/06/17/pvc-and-duct-tape-python-low-rider-recumbent/>
Kudos to this guy. I am still dreaming of a parametric frame construction
made of tubes and 3d-printed lugs - and this comes close.
Jürgen.
<Python Project Survey-small.jpg>
