Key pins and key bushings

[John Ross]

Hi Newwton,
I see what you mean. But some pins seem to have not so much of the ovalness and a
little more of the rounded rectangular shape.
So I would have to say examine the pin, and do not go to extremes.
I still think that rebushing is the proper answer for a loose front bushing.
Unless it is a piano that is not worth the expense of a proper fix.
regards,
John M. Ross
Windsor, nova Scotia, Canada

Newton Hunt wrote:

> List:
>
> Let us get something curved here (as opposed to straight).
>
> Front key pins are oval, almost.  The two sides have a constant radii
> which means that, within certain limits, the interface area between
> the radii of both sides and a bushing remains constant, but relocated
> fore and aft.
>
> This means that the contact surface will remain constant irrespective
> of the angle of the pin until the termination of the side radii.
>
> It is an old wives tale promulgated by lack of fore thought and
> undelineated parameters.
>
> Like any technical solution there are appropriate and inappropriate
> application approaches.
>
> In simpler words: You can turn key pins with no ill effect if done so
> thoughtfully and carefully.  We are technicians, be an intelligent
> one.
>
>                 Newton
>
> John Ross wrote:
> >
> > Hi Richard,
> > I would say, never turn the front pins. Doing that will put a lesser contact
> > area of pin/bushing, and cause faster wear.
> > Regards,
> > John M. Ross