How can I tighten 1870s reed rivets?

[Bassconcertina.net]

Hello, I have a (possibly ulhig) 1870s Chemnitzer concertina. The issue is there are 16 tongues per one plate, and some reeds are of center with the reed slot causing an annoying rattling noise, the rivets that hold the tongues are loose, how would I fix this problem? Thanks.

[Chris Ghent]

There has to be a better place to ask this question. A repairer of chemnitzers or bandoneons would have to have done a few of them. In the concertina world gang plate reeds only occur in old German concertinas and I have not heard of one being repaired as it is not worth the trouble because they are the antithesis of the image of modern German engineering.  
 

If you have to do it yourself one would have to start by tightening the rivet. There is a youtube video of riveted accordion reeds being manufactured and the operator progressively tightens the rivet by placing the head of the rivet on something hard and peening the other end. He hits it a couple of times and then realigns the reed so it doesn’t hit the side and then tightens it more and realigns etc.

[Chris Ghent]

Mmm, should have said, take the plate out of the instrument before hitting it..!