So I built a multi speed bamboo bike and my seat tube is bigger than a standard size clamp on front deraileur clamp. It measures 1.6inch or 40.64mm.
Anyone have ideas on how I can clamp a braze on or clamp front deraileur to this bike? I really do not want to drill holes in the bamboo.

Thank you in advance for any help or ideas you can offer.

I love the way it rides. Now I just need to be able to shift.