I just got a 1975 Steinway B which I plan to rebuild,refinish etc.The previous owner a school had someone(tech) gut the action as for the telflon parts except the back action and install new Steinway parts fairly recently.(hammer,shanks,flanges wippens).
These parts look to be a product of Renner though definitely genuine Steinway parts. Unfortunately these parts are totally wrong for the piano though they look new condition wise.My prep tech who has samples of every shank,flange,wippen combination available on the market configured that the Tokiwa or Renner USA parts we usually use will work fine.I'm just wondering before I do any research what piano(s)where and when can I use these near new parts. I assume they are the pre 1984 Steinway parts manufactured by Renner. I've never used them with all the Steinway grands I have facilitated.I hate to toss them. Any advice would be appreciable though it may be over my head,I can pass any info to my tech and rebuilder.

I suppose the simplest technical way of evaluating the action parts is ..

How do they feel in the piano?

As you already know, the most common symptom is heavy touch weight.

A secondary symptom would be how they regulate.

For example, if the knuckle on the new hammer shank was too small, the drop screw would regulate very high. Sometimes, you can't raise it high enough to reduce drop to an acceptable amount.

I am curious, what exactly makes the parts you have .. wrong?

Larry,Thanks for your reply.You gotta bear with me in that I'm just translating what my prep tech is stating as for symthamatic problems.

The knuckle is 8mm so your above example applies as for one of the problems
The shank is a 16mm shank but coupled with this genuine Steinway wipp you have to raise the capstan a 1/2" which changes the jack position up or forward.
With a Tokiwa copy of a NY wipp/parts which we mocked from all the differnt part combination/manufacturers they felt the best in this piano.Had to actually lower the capstan a 1/2".My prep tech,Mike Farnell of Pacific Piano Supply and who distributes Tokiwa parts in the states said something to the effect that the wippen post is forward or different in some way on the Steinway part.The accelerated action he said has something to do with it.
All I know is that even bench regulated the piano plays BAD with these parts.
It's not a problem with the new parts that I'm gonna use which the Tokiwa or even the Renner USA seem fine but wondering what pianos or application were these parts for.
I read a short ptg. article last night which D Stanwood made mention that these Pre1984 parts from Steinway are wrong and should not be used period. I thought WOW! Just trying to salvage these near new parts for something.Appreciate any more insight from the pros.
PS Mike is delving into the stack as i type.We were only assessing the issues and symtoms yesterday.

Personally I have not found an application that I would use the pre
84 parts.

The others available ALWAYS work out better. I suppose you will never find an application that you would choose to install them on with the other choices available.

It's just not worth it.

Steinway suggests the pre-84 shanks for wippens without fly regulating buttons. Otherwise they say use their current shanks.

Update and correction after further analysis of these action parts.Technically Renner in making this whippen just took the Hamburg body lowered the rep lever 2mm and changed the wippen flange in trying to make this wippen compatible with the NY Steinway. The shank/flange is a hamburg flange with the 16mm shank in trying to conform to NY specs.In conclusion these parts don't work and aren't salvageable for anything which is a bummer! in that they are like new.We tried changing the wippen flange but the other dimensions are still wacked.
Correction,the knuckles are still 10mm not 8mm. I was hoping to use these parts being genuine Renner made Steinway parts but it doesn't look like it. Any other suggestions from the pros ?.

I give old piano parts away to kids. They love 'em! You can also use them for interesting art projects.