I made the rivet tool out of a 5 dollar c clamp.
Back the clamp off untill the cup pulls of the end and it comes apart, grind the end of it down untill its pionty like a nail or screw, then it will work to flare the rivet ends.
Its a little tricky/pita to use but gets the job done, if I needed to use it more than once every 2-3 years I'd buy a good one.
To shorten chains I grind the ends of the pins off and 1/2 way through the side plate with a 4 inch angle grinder then pry the side plate off, you dont need special tools for that either.
If I buy the chain from one of the local dealers they will lend the proper rivet tool tho.