I sure wish I had known about this forum before I started. I have a Briggs and Stratton Service and repair manual (copyright 1992) I got 20 years ago and it's been a great resource. Chapter 13 has all the special tools down to shop towels , washers and nuts. No mention anywhere of this puller that only after reading your message did I know one for this specific engine existed. Glad I stopped pounding on the shaft since It was starting to chip away threads. I think I stopped in time. If you can please put up a picture of the puller/bolt that would be very helpful. Bolt size and tread info would be fantastic. Not one video , article , podcast or manual mentions this puller for the series 6 mower. I watch all the tarydactyl , donnie boy, chickacanic videos and no one mentions a puller for possibly this one crankshaft pulley. None of the others says anything about those threads or a bolt to get it off with. I'm going to dig in my parts barrel and see if I have anything that matches that thread. I do have a lot of taps and dies and might have one that matches this.
* the only bolt puller I can find in this chapter 13 is on page 13-4 part number# 19238. I'll copy that page and put the picture up on here.
I have the Snapper parts manual #06082 with a drawing of the pulley on page 24 but no mention of a puller or how to remove it.