candukid If it is a linear slope out to 2 inches...
That's what I found @Heriko for tapered shafts :
In taper tip construction, the shaft tip will be 0.355” at the very tip and approximately 2” up the shaft tip will become 0.370. The shaft becomes essentially parallel (or follows the normal shaft taper) for the rest of the tip section. Some models (e.g. certain KBS or older shafts) have a slightly shorter taper section and hit 0.370" closer to 1"–1.5" up.
I do not know about tapered bores, but some need a collared ferule.