Possibly insane question...

Do pianos vary in the width of the keys, and thus the overall width of the keyboard?

My first thought was "of course not" - it would make things impossible for pianists! But I've just started practising again at my local church, on an old baby grand by a maker called Albert Fahr. I hadn't practised there for a while, as for a year I was studying postgrad at the RSAMD, and using the academy's wonderful Yamahas and Steinway Ds.

Now I'm back on this piano I'm finding my fingers seem to go to the wrong places - especially in scales. The touch of this piano is definitely hard to deal with (I doubt the action has been looked at by a technician for many years), so that may be it. Or could this piano really have narrower keys?

I'm not talking with any certainty here, but I've certainly found in the past that some older piano's have slightly different shaped black notes, and the different coating on the keys does make a difference, I think in essence though the keys are the same size.

I sometimes play on an old "mini minx" and yes the width of the keys on that piano is slighty smaller. A stretch I'm finding slightly awkward to play on my clavinova causes no problem on the mini minx.

According to wiki...

"Over the last three hundred years, the octave span distance found on historical keyboard instruments (organs, virginals, clavichords, harpsichords, and pianos) has ranged from as little as 125 mm to as much as 170 mm. Modern piano keyboards ordinarily have an octave span of 164–165 mm; resulting in the width of black keys averaging 13.7 mm and white keys about 23.5 mm wide at the base, disregarding space between keys. Several reduced-size standards have been proposed and marketed. A 15/16 size (152 mm octave span) and the 7/8 DS Standard (140 mm octave span) keyboard developed by Christopher Donison in the 1970s and developed and marketed by Steinbuhler & Company. U.S. pianist Hannah Reiman has promoted piano keyboards with narrower octave spans and has a U.S. patent on the apparatus and methods for modifying existing pianos to provide interchangeable keyboards of different sizes."