Use the right tool; when you cant, improvise )
In my post 'The right tool for the right job' (http://prashanthchengi.livejournal.com/61269.html), I wrote about the importance of using the correct tools, but what if the right tool is simply not available? Then, one would need some luck to find out alternative options and then some more luck, to get that alternative option to actually work!
When I started working on my old mountain bike, to replace a worn-out bottom bracket, I realized a couple of things; my bike seemed to have what is generally considered to be the 'fixed' cup on the left side and the adjustable cup, on the right. The cup on the right came off without much ado, but the one on the left was a different proposition. This is what it looked like:
This cup needed the Park Tool HCW-11 or equivalent tool, but finding that at a store near me seemed to be Mission Impossible, as this kind of cup is almost not seen anymore. I found a couple of places that sold the part, but none within Sweden, which meant that it would take days before I could start to work on the bike. Desperate for solutions, I searched around, till I found a youtube video by user BikemanforU, which mentioned how we could come up with a DYI tool for this very purpose. I did exactly as shown, and was able to get that pesky bottom bracket cup off without damaging anything.
I used two M12 nuts, a long M12 bolt and two washers, one large and one smaller. The smaller washer was to ensure that the M12 nut didn't pass through the large sized washer.
The M12 nut was larger than the opening on the cup, so it stayed on the inside, while the washers and the other M12 nut on the outside provided a means of clamping the adjustable wrench in position, around the raised surface of the cup. I had to loosen the outer nut, reposition the wrench and tighten the bolt after each 180 degree twist of the wrench, but it got the job done!
Even after loosening the cup with several 180 degree twists of the wrench, I still couldn't simply use the wrench without the makeshift clamping arrangement, so there was simply no way I would have been able to get it off, without doing some serious destruction, had it not been for this idea. When the cup finally came off, I was much relieved. After that, it took me less than ten minutes to put the new sealed bottom bracket set in and put everything back together again.