Question on plate robustness in 1904 Bechstein.

[Richard Brekne]

Ron Overs wrote:

> Hi list,
>
> Rob Gagnon wrote;
>
> >Plan to move piano across country but heard that
> >Bechsteins had a reputation for cracked plates.  Is this true
> >and generally what precautions should be taken to prevent
> >cracking the struts when moving.  Thanks.
> >
>
> Unless the piano is grossly mishandled, I doubt whether moving it is
> likely to cause the plate to crack. However, the way that Bechsteins have
> been manufactured has much to do with plate failures experienced.
>
> We have rebuilt many Bechstein grand pianos over the years.
>
> It is suprising how consistantly the plate is poorly fitted to the rim
> and pin block in these pianos.
>
> When the plate screws are removed, the plate will invariably will rise
> away from the pin block and rim by up to 3mm and more in some places. It
> almost seems as if the plate set bolts were, in many instances,
> deliberately adjusted to push upwards on the hitch pin plate. This upward
> pressure also encourages the failure of the back posts to inner rim
> joints.
>

The Bechstien indeed has a flex/stress forced into the plate. The
proceedure
for removing the plate is to loosen the plate screws at the rear of the
plate
(furthest away fromt he pin block) first, and work your way around, not
loosening the pinblock plate screws until all the screws around the rim
are
fully removed. You will see the bass corner of the plate rise by as much
as
an inch or so. This is Bechstein... they mean to have good reason for
this.
Something about utilizing the plate flex (such as it is) found in grey
iron.
Source info for this is a Mr Kevin Gouldman who is a Master Piano
Builder
certified as such by the German education system. So its not a "poor"
fit as
such. They do it on purpose. Would be interesting to find out more about
why
they do this

>
> The propensity for Bechstein plates to break is not suprising. Grey cast
> iron is noted for its lack of flexibility. It cannot be treated as if it
> is a piece of wood.

True enough.. Makes one wonder why they do that.. But I think you will
find
that all Bechsteins are such. Anybody got any hard info on this subject
??

>
> Ron E Overs
> Overs Pianos, Sydney
>
> Email: ron@overspianos.com.au
> Web site: www.overspianos.com.au



On the side, and interestingly enough a previous posting on the subject
matter of V-pro the following was written

The flexibility of grey cast is quite surprising in the real world, a
piano
that Del and I had some dealings with, was assembled with out adequate
bracing. ( I may add we are both innocent )
The Torsional stresses and hence plate movement could be noticed whilst
tuning the beast,
and would not stay in tune principally due to plate movement.
Will try to post data next week.
Regards Roger
Roger Jolly
Baldwin Yamaha Piano Centre
Saskatoon and Regina


Seems to me like we all need to do some serious looking around to find
out the real "facts" about iron plates, casting proceedures, etc.etc. ad
absurdum.




Richard Brekne
I.C.P.T.G.  N.P.T.F.
Bergen, Norway