Join wooden poles end to end
If you are going to be swinging this 2-part pike around like a weapon, there will be a lot of stress at the join.  It would be good to spread that stress out.


Obtain pipe the diameter of the 2 poles.  Iron pipe would be strong but harder to work.  PVC would be light and easy to work but less strong.  Copper is expensive but strong enough, easy to drill and looks cool.  
Cut a length of pipe approx. 30 cm.
Slide pike shafts in top and bottom of pipe so they meet in the middle.
Tape shafts in place so they stay put when you drill.
Drill hole thru and thru pipe and shaft.  In one side and out the other.  You could actually make 4 holes in the pipe so each pike shaft has 2.
Thread bolt thru each hole and fix on far side with a nut.


This will be robust for swinging around in your re-enactments because the pipe spreads stress over a large section of shaft.  It will be easy to break down.