What could cause the hammer flanges to get really loose even though wear on the knuckles and hammers is not extreme?
Could the cloth have been defective? THe shanks & flanges were replaced in the early 1980's.

Hammer flange what? Screws? Center pins?

ummm, Jer, the question might be about bushings, if I read the title of the thread correctly....

I have rarely seen loose bushings though, they are usually stuck in there quite well. Now center pins on the other hand.... those are indeed often loose in the bushings.

If the parts are not showing much wear, I would suspect that either the bushing cloth was not high quality or the original pinning was not done properly, at least not properly enough to stand up to the climate in your area. I often hear that techs let a new set of shanks acclimatize for a while in their shop before checking the pinning prior to installation (and re-pin as needed). This could have been omitted. Speaking of that, I recently installed a set of pre-hung hammer on shanks. These came from far away. Maybe I am opening up myself and my client's piano for a center pin problem down the road. Any opinions (without hi-jacking the thread)?

Abuse of CLP ... centers going out of the wood with time.
screws not tightened too much hygrometrics changes (centers goes out more easily in that case)

Lack of voicing (hard impact is hard on the cloth) hammer mass not well centered on shanks,(hammers not vertical enough)
of course misregulation ; tails rubbing on the backchecks, regulation if incorrect can cause wear (compression) of the cloth. centers of lesser quality, if the surface is not good they will ream the cloth

@Jurgen I mostly adjust new pinning with distilled water 5% isopropyl alcohol if too tight, as installing a pin of the same size after burnishing the cloth is not really secure.
(the advantage I find in using the 60 cm long centers is that different sizes can be find, some centers will be 130 mm strong for instance, gauges generally differs a little from the small centers.

I also respect the orientation of the center, as the fiber in the flange is following it (the centers are cut on the opposite side they are inserted so it can be seen)

When burnishing in a drill press with steel needles , the needle goes out in the direction opposed to the future center insertion

I have consistent results on grand hammer flanges taking all those precautions.

Using a support to hold the parts while reaming is also a good idea, the parts will be more square in the end.

a saw lines in the top of a wooden block (end of the grain direct ion) are enough to hold flanges and grand shanks, but a small thin vertical plank with a saw line and flat head screws on one side to regulate to the parts shape, is what was used in the factories to install new (long) centers.

see that at 8:10 on that old movie :

OK, let's back up a minute. how loose are we talking about and how are you determining how loose this is? Number of hammer swings, gram resistance, side play, wide string grooves on the hammer... ?

If the parts are installed in an instrument that is subjected to boiler heat, it could be as simple as the wooden parts shrinking over time.

Some shanks I have ordered from a particular company have had a lot of slop between the bird’s eye and the flange.

I kind of figured as much Jurgen but with as many vague things that people post, I thought I would should anyway.

1980's? That's close to 30 years of wear already.

Hammers where flange screws have loosened up allowing the flanges to move over will create wear on the bushings because hammers are not striking in their original location on the wire groove marks in the hammers. This can force the hammer over each time it is played. It doesn't always take much to eventually create wear on a bushing and this type of thing can do it too.

Sorry, I was not specific enough. THe bushings are so loose that the shanks wobble a good bit from side to side. I have no idea where these were made. The screws were not loose.

SO THOSE RE THE SHANKS SOLD BY A....(SECRET NAME)

and widely used as so good quality parts (for them to know, if they read me)

Perhaps they are those. From a S*******y.

yes , but after 110 years that is no surprise What is , is to find much side play (from left to right, not in the bushing cloth) on new flanges and shanks from a reputed supplier.

To mount them I would have to take out the centers, install 2 small paper /mylar punchings on the left and right side of the birdseye and mount new centers.