Can someone confirm the thread measurements for the big 27mm crank pulley bolt on the M103? I measured it to be M18x1.5, just need to verify if someone has the official spec on the bolt.

Reason being, I accidentally stripped the first thread on the crank when attempting to remove the hub using a puller+socket combination. I fit a 13mm socket which sat perfectly inside the threads and ruined the first thread. I need a tap of correct size to fix the first thread.