fitting bearings to a shaft advice

[Neale]

Just done some quick sums based on rough coefficient of expansion of steel. If your diameter difference is correct, then you will need a temperature difference of around 55C to get enough expansion/shrinkage. So, bearing in oven to, say, 100C, and shaft in freezer to give you around -15C. Difference should then mean that the bearing will drop on with a very small amount to spare, but will grab quickly as the temperatures equalise.

Saying "5000th of an inch" is a bit difficult to interpret. I think you actually mean "half a thousandth of an inch" or "half a thou" or 0.0005", which is the imperial equivalent of 0,0127mm. Shows one advantage of the metric system!

Good luck,