Noninvasive Connections:
https://www.mcmaster.com/structural-pipe-fittings/aluminum-slip-on-framing-and-fittings/
https://www.mcmaster.com/structural-tube-fittings/clamp-on-framing-and-fittings/
https://www.mcmaster.com/structural-tube-fittings/flush-fit-framing-and-fittings/
Not 100% sure what this is used for: http://www.xindawind.com/tube-clamp/57443569.html
Invasive (drilling, epoxy) Connections:
We could also make our own connections pretty easily if we allow ourselves to drill
Materials to use to bond CF together: https://www.permabond.com/materials_bonded/how-to-bond-carbon-fiber-2/
There's a section on connecting CF with rivets instead of threaded fasteners. Overall this would result in less structural damage to the CF I assume: https://dragonplate.com/how-to-connect-carbon-fiber-tubes
The good, better and best way to drill CF: https://www.elevatedmaterials.com/drilling-carbon-fiber/
Bonding 2 tubes of CF (no drilling): http://www.carbonfibertubeshop.com/cut%20&%20bond.html
Youtube comment about drilling a CF Bike frame:
“No, don't drill a carbon bike frame. Carbon frames with through the frame cables have been specially constructed to have those holes and will be internally reinforced to deal with it.
But if you insist on doing it, then you'll have to buy a Dremel and use grinding tips to make the hole NOT DRILLS! A drill will almost certainly snatch forward at some point, creating a big risk that the material around the hole will split. If it does that, you may have to throw the frame away. But any hole you make without splitting the frame will need reinforcing and I recommend that you buy some carbon fibre "braided sleeve" https://www.easycomposites.co.uk/#!/fabric-and-reinforcement/carbon-fibre-reinforcement/carbon-fibre-braided-sleeve to fit inside the hole and teflon tube in several smaller sizes https://www.ebay.co.uk/itm/PTFE-Tubing-Metric-3-15mm-OD-Sold-by-the-Metre-Air-Tube/331894146125?hash=item4d466ec44d:m:m0eLw1oKxdYHZPq29YhQOqg and some epoxy resin https://www.easycomposites.co.uk/#!/resin-gel-silicone-adhesive/epoxy-resin/EL2-epoxy-laminating-resin.html
You will then have to wet out the carbon sleeve with a suitable sized teflon tube inside it, so that you can get it through the hole in the frame. Then you'll have to wiggle and circle the teflon tube about to try and spread out the carbon inside the frame, while also spreading out the carbon sleeve on the outside and smoothing it onto the surface. Then you'll need to leave a long piece of teflon, following the route you want the cable to go, in there till the epoxy sets. The teflon will hopefully not adhere too much to the epoxy and you should be able to remove it once set, then you'll have to do the same thing again, I suggest a minimum of three layers in all. When you do the final carbon sleeve, I suggest you'll need to leave your largest teflon tube in there full length, to help the cable go through. And you'll need to consider sanding down the carbon sleeving on the outside as little as possible to retain as much strength as possible. So the end result may be kind of ugly.
So, that's what I'd do, if I was forced (at gun point) to make holes in my carbon bike frame.
Good luck.”
Comments
Nobody actually says how much a piece of CF is weakened when you drill holes into it - goes back to the knockdown factor from asha's interview. That being said, it would probably be wise to reinforce any holes we drill somehow. We can also try emailing other URC teams who have clearly drilled into their CF in their sar videos. It might be worth knowing if they've had any issues by drilling instead of clamping or epoxy. Anveshak for example just made aluminum gussets and bolted the CF to them, or at least that's what it looks like.
