Hornbeam

[Delwin D Fandrich]

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Yes, I've read all that as well.  Just one more example of the numbers alone
not telling the whole story.  Some years back I compared maple hammershanks to
hornbeam shanks directly, although the tests were not exhaustive.  On average,
the maple shanks had less bend to them.  I did not find that the hornbeam
shanks "transmitted energy" any better than did maple shanks -- if as well.
The repetition lever stop screw (sometimes incorrectly called the "hammer
drop" screw) became loose in the flange much more quickly in the hornbeam than
in the maple.  Hornbeam forks (where the centerpin goes through) was also more
susceptible to impact damage.  The maple shanks were simply "tougher."

There was a greater variation among the maple shanks, however.  In fact, I
suspected that some of the maple shanks I tested were actually made of soft
maple, not hard maple as specified.  The manufacturer of the maple shanks was
not generally noted for its careful quality control procedures.

Del

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Frank Weston wrote:

>  I'm coming in late on this discussion, so maybe someone has already
> provided this information which is taken from a Renner brochure included
> with my latest order of action parts: BEGIN QUOTE"Renner has found Hornbeam
> to have significant advantages because it is more dense in structure, and
> scores measurably higher in bending strength and hardness tests over Maple.
> While we will manufacture to each customer's own specifications, we
> recommend Hornbeam, and Renner USA uses Hornbeam exclusively for the
> following reasons: The enormous bending strength of Hornbeam -- about 32%
> higher than Maple  -- has a particular advantage for hammershanks.  There is
> less warping or back springing when the hammer attacks.  This means a better
> energy transmission of the hammerhead when attacking the string.  The
> greater bending strength of Hornbeam also reduces the sliding and rubbing
> movement of the hammerhead against the strings when the shank is under
> tremendous torque during the attack - the benefit of which is a decreased
> wear and tear of the hammerhead felt.  Another important benefit of the
> increased bending strength is less re-traveling of the hammers. The use of
> Hornbeam, with our special bushing felt, are important factors in producing
> the superior bushing centers in Renner action parts.  The grain direction of
> the much denser Hornbeam is chosen is such a way that the flange bushing
> centers have an optimum position towards this direction.  this guarantees an
> enormous strength in the section of the two bearings within the flange, as
> the center will have a better fit when it is pressed directly into the wood
> in this direction (e. g. for whippens, underlevers, etc..).  Also, the
> pressure put on the center can be increased by 23% when using Hornbeam,
> instead of Maple before it will remove within the wooden part."END OF
> QUOTE Although a lot of the terminology is incorrect in the strictest sense,
> and the translation from German is confusing, a few points come through
> clearly: 1.  Renner claims to use Hornbeam because it is a structurally
> superior wood to Maple, according to them 33% greater tensile strength, 3.5%
> greater Brinell hardness, and 32% greater bending strength. 2.  Renner
> implies they will manufacture using what ever wood a customer requests.
> They don't say how small an order they will take or how long the
> delay. Frank Weston
>
>      -----Original Message-----
>      From: Delwin D Fandrich <pianobuilders@olynet.com>
>      To: pianotech@ptg.org <pianotech@ptg.org>
>      Date: Sunday, June 06, 1999 2:13 PM
>      Subject: Re: Hornbeam
>
>      dporritt wrote:
>
>     >  Del Fandrich writes:And who -- besides Renner, that is --
>     > really believes that hornbeam shanks are superior to even
>     > relatively decent maple shanks?
>     >
>     > Regards,
>     >
>     > DelI don't know as much as I'd like to about the relative
>     > strengths and weakness of Hornbeam and Maple.  However, I really
>     > like the Renner shanks, bushings, center pin accuracy, friction
>     > consistency, shank shape, treble tapering, phone curtesy, order
>     > turn-around time, pleasant dealings....... that I get from
>     > Renner.  I suppose they could make good Maple ones
>     > too.dave_______________________________________________
>
>      Dave,
>
>      Sorry.  I think you misunderstood.  I was referring only to the
>      actual material used, i.e., hornbeam as opposed to maple.  As for
>      the rest, I'll agree with everything you've said except perhaps
>      for the friction consistency.
>
>      And I do wish they made maple shanks.  Perhaps even offering us a
>      choice between the two.
>
>      Regards,
>
>      Del
>


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