Changing roller size.

[Jon Page]

Steam Roller,

The problems I have encountered with S&S replacements have been in the
center pin to core radius, nothing to connect with actual roller diameter; or
maybe I just didn't notice.

Regards,
Jon Page


At 08:19 AM 09/01/2000 -0600, you wrote:
>Hi Jon,
>             So there is some Englishman in you, Roller indeed??????
>Just the observation's on Steinway's when some one installs the wrong
>knuckles,and the severe alteration in touch weight, power, and repitition.
>Not enough case studies to offer an opinion. O ther than the whole action
>is screwed up. <G>
>
>Regard Roger
>
>
>
>
>At 09:03 AM 01/09/00 -0400, you wrote:
> >Graeme,
> >
> >I have not experimented with this alteration but I can envision a few of
> >its consequences.
> >
> >With each size smaller roller, the capstan would have to be turned up to
> >raise the wippen
> >to maintain hammer blow. My concern would be where the 'magic line'
> >intersects the
> >capstan/wippen cushion contact. So if it came down to altering knuckle
> >height to correct
> >the magic line juncture (I'll call it the median line); I'd sooner change
> >the capstan location
> >to improve leverage.
> >
> >Also a smaller knuckle would have the jack clearing it sooner due to its
> >diminished radius.
> >With this decreased connection period, will it affect the dynamic control?
> >
> >As to how this attenuation might affect leverage, I can not speculate.
> >
> >I've limited my knuckle selection to the center pin to roller core radius.
> >As pointed out
> >during the Renner USA  class in Arlington, as the c/p to knuckle radius
> >increases; so does the
> >knuckle diameter so as to maintain wippen attitude within the system. So
> >the 15.5 mm radius has
> >the 9mm knuckle and the 16.2 & 17 mm radii have the 10mm roller.
> >
> >Anyone do some "scientific" rescearch?
> >
> >Jon Page
> >
> >
> >At 08:52 PM 09/01/2000 +1200, you wrote:
> >>Hi list,
> >>
> >>I was speaking with a technician friend last night and we were discussing
> >>another tech acquaintance (quite respected locally) who has been replacing
> >>grand rollers (knuckles to some of you) with smaller sized ones.
> >>
> >>In his opinion he achieves a finer regulation, faster repetition etc etc.
> >>So as I understand it he is say replacing a 10mm roller with 9mm and
> >>sometimes 8mm.
> >>
> >>My take on this is that the geometry would be altered elsewhere. I'm not
> >>knowledgable enough though to know what the possible negative effects could
> >>be, if indeed there are any.
> >>
> >>Could some of you with experience in this throw some light on this, whether
> >>it works well or not at all.
> >>
> >>I'm curious to say the least.......
> >>
> >>Many thanks,
> >>
> >>Graeme Harvey
> >>New Plymouth
> >>New Zealand.
> >
> >Jon Page,   piano technician
> >Harwich Port, Cape Cod, Mass.
> >mailto:jonpage@mediaone.net
> >~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> >
>Roger Jolly
>Saskatoon, Canada.
>306-665-0213
>Fax 652-0505

Jon Page,   piano technician
Harwich Port, Cape Cod, Mass.
mailto:jonpage@mediaone.net
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~