Too much to ask for an arbor.

[Scra99tch]

I am looking to add a few 3" CBN 1A1 and 1F1 wheels to flute on the cnc grinder. I have a bunch of hydraulic tool holders with 10mm shank sizes that have a projection of about 2". Would it be unreasonable to try and make an arbor that stick out another 2" max running those wheels close to 6k rpm or am I going to be regretting this quickly.
The hole size in the wheel is 1" so I wanted to see if I needed to buy a 1" tool holder and call it a day.