But think of all the $$ you could have made selling that one for someone else that used a puller like that on theirs and bent it.
The threads should be fine in the middle of the shaft. Just get the proper sized bolt in a grade 8 and a fender washer with a nut. Screw the bolt in (don't bottom it out) with the nut and washer already on there. I did that once on a chevy and did use 3 fender washers and some spray lube in the middle so one can fit solid on the pulley, one solid on the nut, and both slip on the center one. Then crank down on the nut to push the pulley on.
In your case, to push the steel center piece on. This can be eased by heating that steel center section a bit... maybe in your oven at 350 for a few minutes. I'm not sure if that part is heat treated so not sure if it would hurt it having the heat.