In a pinch, you can use a hard bolt, by comparison, to chase, not cut, threads in a softer metal.

Take and old left pedal and an old right pedal, ones that you will not use again. Using a very find blade hacksaw, cut a slot or two or three equal distance from each other. The slots run parallel to the center line of the bolt.

Now, using lots of lubricant, thread the correct pedal spindle into the correct crank arm. In a wee bit, back out to clear the groove, and in a wee bit more.

That's how one chases threads when there is no proper thread chaser, or tap(s) to be had.