Follow on to "Expander plug refinement."

I’ve been doing a lot of reloading lately and I find that the mouth expanders do seem to form a flare quite quickly into a cup like shape. This reminded me of dromia’s post from last September and how he described the issue (http://noebulletmolds.com/smf/index.php/topic,2650.0.html). I would have appended to that thread but it told me it was older than 120 days and I should start a new one (blatant age discrimination!  ). Dromia seems to use a two step approach to fix this by following the expander step with the Lee universal expander to straighten out the round. My own approach is to fiddle around with the thing until it forms just the right flare. So perhaps there is something that can be done regarding this? I’m going to take one of my spare expanders and throw it in the lathe to see if I can just remove that roundness so that the flare forms at a straight, rather than rounded, angle.