Don D. rightly points out that newer Suzuki reedplates (including those on my Overdrive) are spot welded rather than riveted, and probably wouldn't be worth the effort for reed replacement. Suzuki does sell replacement reedplates for the Promaster, so at least you don't have to trash the harp should a reed go south.
I was just about to go out and buy a Farrells or Romel reed replacement tool when I read Pat Missin's extremely helpful article regarding reed replacement contained in his wonderful "Altered States". In it he describes using a 1 mm punch and a hefty comb instead of a specialty tool. I think advice from someone doing more reed replacements in a day than I do in a lifetime is well worth checking out, so on my way home one evening I stopped at Home Depot and bought myself the smallest pin punch I could find (about $4, I bought two so I could mess on up), took them home to the grinder and made one that is just the right size. I use an old MS Meisterklasse comb for support and a tack hammer to tap, and voila: reed replacement tool! I have a miniature machinist's anvil I bought from Micro Mark a while back that I use when installing a new reed to seat them. I've now replaced a LOT of reeds very successfully, with nearly no failures, and I kept about $40 in my pocket (Okay, $30 if you count the $10 I spent on the anvil).
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