I recently bought a Robland 5 in 1 combo machine, and I'm new to shapers. I've been trying to do as much research as I can, but one thing that I haven't seen anywhere else is a spindle that is half 1 1/4", and half 3/4". All examples I've seen have always had a single diameter for the entire spindle. I'd assume it's for the benefit that you can either choose to use a larger heavier head on the bottom, or choose to use a smaller lighter head at the top.
Has anyone seen this style before? Also if I were to use sleeves to make the entire spindle 1 1/4", is there any concern? I ordered a 125mm Whitehill Combi head, and I don't plan to need it's large tenoning feature where the head needs to be mounted near the top of the spindle, but I'd like to know if I should avoid ever using the head in that way.