In Which Tools Are Aquired

I have purchased a Dremel.

In order to miter the other ends of the down tube and seat tube, it is first necessary to fit them into the bottom bracket shell in order to scribe the appropriate lines.  This has so far proven impossible, since the unfinished interior diameter of the BB sockets is a touch too small to allow the tubes to fully penetrate.

I have been diligently filing for several hours, but there are a couple of complications.  First, the filing needs to be done in a very cramped space - the main body of the BB shell prevents the file from traveling more than two or three inches (the length of the socket plus the diameter of the shell).  It effectively limits me to using the small needle files and course emery paper, neither of which removes much material; these are really meant more for finishing work.

Second, I have eczema on my dominant hand which makes work fairly painful after awhile.  I wear gloves when I can, but it limits my ability to work with emery paper (the fingers of the glove slide, or the paper slides against the glove), and the gloves end up binding in the BB sockets.  I generally lose the fine motor control and tactile feedback that you get from gloveless work.

So, the Dremel.  A grinding wheel attachment should fit nicely into the sockets and open them up enough to accept the tubing.  There is a risk using power tools here, and it's a reason I've avoided using them up to now - they remove material much faster than manual tools, which greatly increases the risk of taking too much metal off the sockets.  The most likely "bad" outcome would be taking the sockets out of round, but if the gap between the socket and the tube is too great then silver soldering will not be possible.  As always, going slow and steady will be paramount.

I may try using the Dremel on the tubing also, but I think the half-round file has been doing an excellent job so far.  Whenever I manage to install a real workbench in my shop space, I may also invest in a bench grinder.  The new tool should arrive in a few days.