I am speccing a new shaper and it will come with a single 1 1/4" spindle (I am in the USA). 30mm and 40mm spindles are also available. I've been looking primarily at Whitehill and almost all of the tooling is available in 1 1/4" and 30mm. Some stuff is also available in 40mm but I can't find anything that is *only* 40mm. Is there any reason to have a 40mm spindle?
Motor sizes are 10 hp, 13 hp, and 15 hp. 10 hp feels like it should be sufficient but the up-charge to 15 hp is small compared to the total cost of the machine. For a sliding table saw or shaper is a 15 hp motor nice to have or complete over kill. These machines are for a home / hobbyist shop and will probably be with me for life.