Geof means by "shower", the flood coolant will be coming out of the spigot like a hose, and the TM-1 being an open design will be flinging coolant all over the place, hence the "shower" you be receiving lol. 1-3 are all correct, use uncoated carbide for aluminum and use coolant on it. TiCN is for alloy steels and stainless steels, AlTiN is a dry machining coating. You can always call the manufacturer of your carbide and get tech support from them. MSC http://metalworking.mscdirect.com/ has great tech support and will get any technical data or personal help from any of there suppliers.