You mention heating with MAPP gas. With the mass of the spindle you may well need more heat than a bottled MAPP gas torch can provide to heat the entire spindle end apart from the pin (to the extent possible). I'd try to get an acetylene torch and heat it thoroughly before whanging it with a good sized hammer and an appropriate punch. If you see that the pin is mushroomed consider grinding it flush to eliminate that interference from the equation. Drilling it out is a bit dicey, as it's a tapered pin and drilling an easily get into the spindle vs the pin.