The inside bend radius is a function of the tool used to make it. In general, you should use an inside bend radius at least 1.5 * material thickness. However, what you specify may not be what is available. Check the radii of the available tools and select from those. You might want a .045" radius but you'll likely not find it. The tools we used had nose radii of .030, .060, .090, etc.
The optimal sheet metal bending radius depends on the thickness and the material. Brittle materials require a larger radius. Take at look at the following table.
I believe that nofear asked what the inside and outside bend radii are. The bend deductions should be left to the sheet metal fabricator. The fabricator we work with seems to trust SolidWorks, if that is any help to anyone.
My old Atlas Alloys catalogue has a table showing the forming characteristics for a ninety degree cold bend of aluminium sheet. For a thickness of .065" to .128", you multiply the thickness by the following numbers to get the inside bend radius.
This table is partial, and I have _not_ checked to see if it agrees with the web link above.
One of the morals of this is that there are certain grades of aluminium that are very good for sheet metal fabrication, and others that are not. 6061-T6 is a popular machining grade, but it cracks when the sheet metal guys try to bend it. Sometimes it cracks afterwards, after delivery to the customer.
The outside radius is the inside radius plus the thickness.
The best modern way to be sure is to cut a sample of material. Measure the exact dimensions, have forming put a few 90 degree bends and then measure all of the legs. You can get your bend radius and k factor by doing this. The tooling used, method used (coining vs air bend) these will all impact the amount of stretch to the material so run some tests and you will be suprised how accurate you can get it.