An all carbon bike?

A while back my awesome LBS gave me a box of carbon tubes and lugs and said “You’re the right person to give these too!”. And with that I had 4 frames to build, one of which I’ve completed.  Take a squizz:

The process wasn’t a simple one. Here’s what I did:

  • Bonded all carbon tubes and dropouts together
  • Sanded and filed those back.
  • Drilled and riveted front derailleur clamp
  • Drilled and set water bottle bosses
  • Drilled custom internal cable routing
  • 3D printed custom rear brake boss
  • 3D printed cable stop for front derailleur cable
  • Masked and handpainted the colour stripes with enamel paint
  • Flat black enamel spray followed by 3 coats of gloss enamel spray.

 

What does this mean for bamboo? Well, I don’t know at this stage. It’s certainly easier working with full carbon, pre-made tubes! Maybe there’ll be another bamboo bike made soon… only time will tell.

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The Samurai is complete!

After successfully completing the frame strength testing I built up The Samurai on Saturday night and now she’s all ready to be packed up and shipped off to an eagerly awaiting owner in Sydney.  Click on the pic for all the details and photo gallery!

Here’s a video of the build too:

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The Samurai has passed the frame test!

Today my 4th frame, the recently finished The Samurai, underwent my quality assurance testing that I do on all frames. The video below details the test and shows that the frame is strong and passes the Australian Standards for Frame and Fork Assembly. Stay tuned for a time-lapse of the parts build!

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3D Printed Bamboo Bike?

A collection of 3D printed cable stops

So I’ve been bunkering down in the Melbourne winter in front of 3D CAD programs designing various parts for the next bamboo bike. My aim is to reduce the amount of manual labour in the manufacture of the bikes and increase their quality, but still allow for individual geometries and styles. There’s a guy on Instructables who’s made a Custom 3D printed carbon fibre and aluminium bike and a lot of what he’s done is the genesis of my ideas for how to go about making custom molds that could be used with bamboo. There’s also this guy who’s made an amazingly detailed frame using 3D printed stainless steel lugs and carbon fibre poles. The triangle cutouts in the lugs are no doubt to save weight – as with 3D printing the amount of material you use is the main cost, and there’s limits to how thin walls can be (~3mm). So thick and chunky but with lots of holes in it seems to be the way to go.

This all sounds well and good, but there’s some caveats. The material properties of 3D printed stainless steel are not necessarily the same as regular steel. It’s infused with brass as part of the process, which, along with the process used, makes it much more brittle than normal. Regular stainless steel has an elongation of around 23%. 3D printed steel only has 2.3%. That’s a huge difference. There’s other 3D printers (like the one the guy used in the video above) that claim different material properties that are closer to normal stainless, but by the looks they’re also very expensive.  I’m hoping the material technology will get better in the next few years so that this won’t be an issue.

So far I’ve modelled and produced some cable-stops which are specifically designed for use with bamboo or carbon fibre frames. Here’s a close up pic of one made from plastic:

A close up of a 3D printed cable stop. The roughness is due to the manufacturing process, which uses extremely thing layers of plastic built up over each other and welded together by a laser.

What sets it apart from a regular cable-stop is the curvature on the bottom of it is designed for thicker tubing and the tabs on either side have holes ready for wood screws so it can bolt right on. It’d probably be fitted with a dab of epoxy as well to help it stick properly.

I’ve designed it to be usable for both gear and brake cables, but I’ll have to do some strength testing on its use for the latter as there’s a lot more force going through a brake cable than a gear cable.

If you’d like some for your own project the cable-stops are available to buy directly from Shapeways, the 3D printer I’ve used. Plastic ones are $7 a pop plus postage. Stainless steel is a fair bit more.  I’ll soon be adding a double and triple stop for use along top-tubes.

I’ve also designed a head-tube badge and had it printed in both white and black.  I’ve coloured in the lettering on the white one to make it stand out, and I’ll probably do the same on the black (white lettering no doubt).

Two 3D printed head-tube badges made from “strong but flexible” plastic.

The next step is to start to model a set of lugs themselves. I want to be able to design them in such a way that the geometry can be changed easily and a new model produced from the changes in geometry semi-automatically. It’s a big ask, and there’s a lot of work involved, but stay tuned and it might just happen.

 

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Shooting a Panda

The Panda was finished a few months ago, but up until now I haven’t had a chance to show her in full glory. Until now…

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