Originally Posted by
dddd
The blade totally glances off of the relatively hard Reynolds 531 seat tube, so no danger of cutting into the seat tube.
This sounded odd to me; 531 cuts easily with a file, and Diablo claims a tooth hardness of 62 (Rockwell C). Reynolds 531 has a UTS of about 130 ksi unbrazed, which equates to less than 30 Rockwell C. This makes sense to me, files are usually 50 Rockwell C or harder.
I'd be having a really good look down the bore of that tube.