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I hate to see a query go unanswered. I think most of us would say a "A fret crowning tool what?" (myself included). Perhaps a guitar repair luthier website like Frank Ford's (Gryphon Stringed Instruments, Palo Alto, CA) www.frets.com web site would be better informed as to what you are asking. That said, you might be able to sand down your frets to resurface them by using a long, narrow sanding block. Find a good piece of wood (nice and level, squarely cut) and glue on (rubber cement) some fine grain sand paper (400 grit) and give it a try. If you are just looking to re-shine your frets, try fine steel wool, but be careful not to scratch the fretboard. In the U.S. they sell blue painter's tape which you can use to mask off the wood parts of the fretboard you want to protect. If that is not available, you can use masking tape, just be aware that masking tape can dry really hard if left on for too long, or exposed to the sun. So you can use it, but remove it shortly after sanding. Hopefully, what I have said answers you question.
Well, fret crowning and shaping was done for many years before there were dedicated tools such as crowning files and neck jigs. These devices were developed mostly by the need and desire to do it faster and certainly require less experience to develop a successful technique, and are likely to give more accurate final results.
There are certainly alternative methods, but to give any advise or consider ideas, it would help, as Oilyfool mentioned, to know what exactly you are trying to accomplish. You mentioned "re-fretting" in the topic line, then mentioned "re-crowning" in the discussion, with no mention of the condition, or symptom you are hoping to "fix".
As a general rule, re-crowning is done to correct the "flattening" of the fret tops after material is removed while "truing" the frets. Even with the modern tools, this is a job that could easily make matters worse in inexperienced hands.
In addition to the links provided above, there is some fret installation and finishing information here.
Hope that helps, have fun!
Thanks for pitching in, guys.