Originally Posted by vpiuva
Now since you already have the stomach to grind your crankset, you may want to try this: drill a hole at the end of the crack. The hole diffuses the stress around to a greater area - the circumference/ surface area of the hole.
I came here to say the same exact thing. If this technique works for cracks in glass and plastic it seems logical that a material like aluminum would also benefit from its use. With a dremel you may be getting rid of the crack but you may not be able to create a uniform shape which may just add more stress points in the future. A good sharp drill bit and some careful drilling with an appropriately sized bit would be what I would use- long before taking a dremel to the area.
*edit
and a drill press would be helpful if you have access to one.