In reply to TLitchfield:
The best option that has worked for me on multiple sets of poles. Missus also leaves them whole. You should always collapse them and spray lithium grease or wd40 in them after use.
Put one section in the vice wrapped with a rag. Don't over tighten and crush the section just enough pressure to hold it still. So a bit of playing around is in involved tightening as you go.
Next add two sets of mole grips one on the collar one on the other section again with rags to stop scratching. The key is to hold the two sections still and turn the collar with the mole grips. if the whole pole turns you will shear the plastic tab which holds the sections together. If this happens mountain boot company will set you a replacement. It happened on the first pole I did. Could could do it with three sets of mole grips put your doing to need an extra set of hands.
Be gentle and don't rush. Last thing is if you can get hold of Kroil this should help lubricate and ease the process.
Cheers Dave