[katsooba]

i did not apply any heat,

i welded the 3rd gear cog to a 1 meter iron bar and mounted the ring i made on a flat surface, and then worked in a slow and steady pace, took me something like 10-15 mins to unscrew that thing, but i made it without too much effort, just slow work of quarter of a turn at a time
i can take a pic of the tools i have made when i drop by my warehouse next week