Tuesday, December 13, 2011

Shopping trip #1

Today we are tired and content after our first trip to get materials and tools.

In the morning we took measurements on the 3D-model. It added up like this:

ca. 24 meters of aluminum

ca. 100 bolts

ca. 100 nuts

After that Andreas went and borrowed a Nihola cargo bike from the local Irma supermarket. They lend out the bikes for free. You do however have to leave 500 dkk ($90) in security, which will be repaid when the bike is returned unharmed. It's a great deal offered by the local Agenda 21 office in collaboration with Irma.

Then we were off to Glostrup, about 10 km west of Copenhagen. It was nice to get some fresh air, although it was a cold and rainy day. See map of route here.

In Glostrup we passed Harald Nyborg to pick up some tools for the Bicycle Innovation Lab workshop. We got a small drill press, a cordless drill and a heap of drills and bits.

After that we visited the friendly guys at Metalcentret. There we bought 24 meters of 25x25x2 mm aluminum square extrusions, weighing around 12 kgs and costing a 1.162 dkk ($207).

We secured it to the bike with strips and headed home. If anyone wants to do the same, some rope would probably be a better idea. Also remember to tie the extrusions to the bike in a way that they do not scratch the frame. Also remember that Metalcentret accepts cash only.

Sunday, December 11, 2011

First steps

Last week the HubJohn took its first shaky steps into physical reality. It included a couple of stumbles.

Setbacks included Søren running into a tight dealine at work, forcing us to postpone our shopping trip to Metalcenteret. Secondly the nice man at SKF revealed that the bearings we'd hoped to use for the front hub steering mechanism cost 1300 dkk / $230 a piece, which is about what we hope to pay for the entire frame. In order to make any sense the hub must be both cheap and easy to build, so it was back to the drawing board. We are now considering both off-the-shelf car-components and a CNC cut bolt-together sandwich assembly with roller bearings. Concept sketches for the sandwich are shown below. Let's see what happens when these new ideas hit reality.

Since we were not able to get the aluminum for the full scale bike this week, I picked up some balsa wood at the local hobby shop, which Søren turned into a 1:100 scale model of the lower frame. Balsa is a very soft and bendy wood, but the model proved to be nice and rigid. This seems like a good sign of the strenght of the Czech Hegehog assembly method that we are using.

Czech Hegehog

Based on the N55 XYZ SPACEFRAME VEHICLES building system - www.n55.dk

On tuesday we'll be at it again:)