Banchad

Hello all,
I'm making my own frame at home out of carbon fibre but I've run into a road block. I am unsure as to how to make a headtube or a bottom bracket shell.

The main problem I am having is the headset bearing cups. I am currently experimenting at moulding these out of carbon to be able to be bonded into another CF tube that I am going to make but I don't know whether this is a good route to follow.

With the bottom bracket I am undecided as to whether to buy and use an existing BB shell or attempt to make a CF tube for a pressfit bracket. I want to use Shimano Ultegra 6800 cranks and I believe the best route to take would be to bond an existing shell in but I am not sure.

Any advice would be greatly appreciated!

Andrew R Stewart 

I would strongly suggest that you retain metal contact points for the components. So a SS Bb sleeve bonded into the carbon and a SS head tube also bonded in. This way you can machine the needed specs prior to bonding and know that all will be good after. I also suggest that you consider staying away from a press fit BB. They are well known for fit up/noise issues. Threading has stood the test of time for a good reason.


If you can search the archives for others' working with carbon for more specific techniques. Also go over to VELOCIPEDE SALON and do the same. there are some very experienced posters there who have gone through exactly what you're beginning. Some companies make the sleeves/headtubes ready for bonding. IIRC paragon is one. Andy.

reddog3

If I were tempted to build using CF I'd research everything I could find regarding Crumpton. Over on the now defunct "Framebuilder's Collective" Nick Crumpton un-selfishly shared some of his techniques. The info is still there in the "Resources" section in PDF form. Scroll to the bottom of the page. Sorry for not providing a link.

CliffordK

One should be able to machine carbon fiber somewhat, but I agree, there would be benefits of using say a Titanium headtube machined for an internal headset bearing, and the same for the bottom bracket.

You could potentially design a truss between the two ends of the head tube or bottom bracket shell. Or, potentially judicious "drillium" That could help improve the bonding of the carbon fiber to the shell.

Shwnmtthws

Banchad, how is the progress? what did you choose with the head set? what epoxies and fibers did you start with?