linseed oil should do fine, as others have said. if it feels slippery some balsom or pine sap rubbed in right at the end of the handle can give a bit of control (if it's the gransfor handle without a poll).

i wonder about the oak too. i've had good success with balsom poplar, both upright and end grain. it soaks up the axe really nice, and makes a pleasant sound.

on the axe handle tip- discovery--> i've always wanted to try repairing a broken handle with a splice- just tried this and it seems to have worked so far. will post pics.