I am doing a project which calls for putting batteries that are 26mm wide into the seat tube. My issue on my chromoly frame is that the (braze-on?) steel, threaded mounts protrude on the inside of the frame around 3-5mm. Is there a way to file these down without removing the mounts or hurting my frame/paint? It's a bianchi frame with columbus tsx, and the last thing I would want to do is damage it, but I would really like to take a little bit of material off on the inside of the frame.
I think that total threaded length is 8-10mm, so minus 2-4mm shouldn't effect cage mount robustness too much, and I won't be using them to carry heavier loads anyways.