The reamer you need is tapered you need the 19mm one and luckily they are back in stock. be carefull when you order as i accidently ordered two but theyre not at all expensive.
I set mine up in the pillar drill and ran it on a low speed keep checking the fit of the maxi ball joint as you ream the hole.
you want maximum egagement of the taper but dont go too big or youll end up scrapping the upright.
Ray
