The serious answer is use an abrasive cutoff disc.
The semi-serious answer is:
Get a length of string two or three feet long.
Tie each end to a little bit of wood to give a grip.
Smear grind paste along the middle eighteen inches of the string.
Loop it over the shaft at the point you want to cut.
Pull it back and forth replenishing the grinding paste as needed.
This will work but I wouldn't want to arm wrestle you after you have finished.