You say Stanley no 5 so your plane is Bailey pattern with lateral adjusting lever on frog. Changing angle of cutting edge is the purpose of this lever. Push towards the corner you want to pull up. 

Here shown in instructions from Stanley documents:

[![enter image description here][1]][1]

[![enter image description here][2]][2]

P.S. If your plane is very early model, "pre lateral" as it is called, or if lever is broken from frog you can still adjust. Using a small hammer hit lightly the side of the iron with projecting corner


  [1]: https://i.stack.imgur.com/9Jr8p.jpg
  [2]: https://i.stack.imgur.com/AunGq.png