The efficacy of properly applied percussive maintenance

Sometimes you get fittings that don't live up to the assumed notions of doing exactly that. My advice is really simple. If you have something thats either antique, hand crafted, not yours or can';t be replaced, err on the side of caution and modify the other side of the fitting. In this particular example, that would be the top of the tsuka.

However, if the fitting is an alloy, cheap repro, production line, easily replaceable or is yours and youre feeling lucky, sometimes a little 'adjustment' is all thats required.

Exhibit A)

From this photo you can easily see that the fuchi has had a bad day. however, placing it top down on a solid yet softish wooden surface, using another piece of wood (or as I did, a square punch) on the inside, pressing against the deformation will allow you to employ a hammer and with a little thud thud you can encourage it back into place with minimal scratching.

You can see there are a few marks here but this is perfectly acceptable and is hidden no matter what you do with it. 

Problem solved. This fuchi is now ready for action.

Don't do it with valuable stuff unless its yours and you're sure you wont ruin it. :)