Bearing interference fit / press fit

[m_c]

In steel you normally aim for 1 thou per inch undersized for a press fit. In Ali, if the parts are going to get hot, you'd maybe aim for 2 thou so the bearing doesn't slacken off when things warm up.

[boldford]

In steel you normally aim for 1 thou per inch undersized for a press fit. In Ali, if the parts are going to get hot, you'd maybe aim for 2 thou so the bearing doesn't slacken off when things warm up.

That sounds a darn tight for a bearing. I'd use that sort of fit betwixt a 3 1/2" or 5" gauge loco wheel and axle. I suspect that amount of interference is going to crush the outer race on to the BBs?