This looks like a possibility, they say they do made to order gears as well, might be worth calling up their applications engineers and seeing if they can find something that fits, and if not, what it would cost to make a set for you. You can also call up DC Morrison and ask them if they can tell you where they got the gears for the mill, since they are no longer selling Burke parts, they might tell you, or might even have the specs for the gears instead of having to guess.
Since you are replacing both gears, and will likely need to modify them in some way, I was going to suggest metric gears, but it looks like the metric sizes are not close enough to what was in there. For metric gears, I use Maedler North America, attached is the product page for bevel gears with a 2:1 ratio, the module 2 in a 15/30 gear pair is a bit smaller than you need, and the M2.5 is bigger, so might not fit. I couldn't find any metric gear suppliers that make other than a 15/30 gear set in that size, but if you can find someone that makes 16/32 or 17/34, then it might be a good size fit.
www.maedlernorthamerica.com
Linn Gear Co.
Linn Gear manufactures stock and custom sprockets, gears and other mechanical power transmission components for industrial applications.
www.linngear.com
Since you are replacing both gears, and will likely need to modify them in some way, I was going to suggest metric gears, but it looks like the metric sizes are not close enough to what was in there. For metric gears, I use Maedler North America, attached is the product page for bevel gears with a 2:1 ratio, the module 2 in a 15/30 gear pair is a bit smaller than you need, and the M2.5 is bigger, so might not fit. I couldn't find any metric gear suppliers that make other than a 15/30 gear set in that size, but if you can find someone that makes 16/32 or 17/34, then it might be a good size fit.
www.maedlernorthamerica.com