Hammers knocking, floating centres :/

[Mrs Piano]

Hello, I've just joined up to ask a question. I have a 6 octave Barratt and Robinson, floating centre action, plastic key bushings. Several hammers in the middle octave, from Middle C upwards, have begun to knock. I've checked the flange screws and they are all tight (I'm a qualified tuner/technician, but haven't worked in the trade for 20+yrs). So, my question: is it possible to cure the knocking? I have no experience of working on floating centre actions and would just like to have some ideas before enlisting the services of a tuner/technician. I'd like to keep the piano going: I've been teaching on it for a long time, and it's a good little workhorse. One desperate idea I had was to swap over the knocking hammers with some from the (unused) very top treble, removing and swapping over the heads of course. Any thoughts on any of this please? Many thanks in advance :)

[Barrie Heaton]

While at the time, the floating centre seemed a good idea in the 70s. They are now proving problematic the actual floating centre itself is still fine; however, what you will find is the centre pin that goes through the wooden part of the butt is the part that is clicking.

To fix this problem, you have a few options.

As you cannot come up a size in centre pins like you would with a normal flange. You have to decenter it, plug the hole in the butt redrill and then put a 23 pin back in.

The method I used to use years ago is to change all the flanges to normal conventional felt bushed flanges. Then put a 24 pin. However, the normal flanges gates are wider than on the floating in centre flanges.

There is another option, but I've never done it myself, and that is to remove the float in centres and replace them with conventional bushings.

[Mrs Piano]

Barrie, thank you for taking the time to reply: I really appreciate it and your advice has definitely given me some ideas for options. Kind regards :)