[pianotech] key making specs

[Mike Morvan]

Dave,
    We've made new keysets and have used maple and basswood for the shoes
and buttons, most customers will specify what they want. We also make new
button stock out of basswood, soft maple and poplar and up until a few years
ago we've sold mostly basswood, now the trend is reversing, last year we
sold 3 sets of maple to every 1 set of basswood. The hardwoods are
definitely popular now.  Having  had the good fortune of working on new and
old keyboards from Germany, Japan, China, England, and the U.S. we are quite
surprised at the different schools of thought. Some manufacturers are using
basswood, maple, cherry, poplar or beech for buttons and shoes (both
flatsawn and quartersawn) and some manufacturers are not using shoes,
buttons or inserts at all, simply relying on the sugarpine, spruce or
basswood material that the keystick is made up of for the balance hole,
which is insufficient and probably part of the reason that other harder
woods are being sought out for these spots. I've also seen the same
manufacturer use different materials for buttons, shoes and keysticks
depending on the cost of the piano and whether it was an upright or grand.
Having said that, it gets real confusing as to what is trying to be
accomplished and why. Quality and longevity? Cost? Ease of manufacture? Who
knows, but I do know this:
What causes

Let's finish,
>>> Having said that, it gets
>>> real confusing as to what is trying to be accomplished and why. Quality
>>> and longevity? Cost? Ease of manufacture? Who knows, but I do know this:
>>> What causes "the need" to ease keys is more important than the selection 
>>> of wood species currently being used for either buttons or balance 
>>> holes, the problems will be nearly the same regardless of species. All 
>>> things considered, if one looks at the numbers, the expansion and 
>>> contraction figures for the different wood species currently being used 
>>> is pretty close and don't forget, the cloth in the mortise will move 
>>> sooner and further than the wood.

Why would one ease the maple or basswood of a button? The cloth is the "wear 
item" that should be eased not the wood. If one has to ease the wood than 
the wrong size cloth is in the mortise, or the mortise is of the wrong size, 
or the mortises are of inconsistent sizes as with older keyboards after 
several rounds of rebushing. Also, easing the wood is not a permanent 
solution just temporary,  moisture in the air will eventually expand the 
fibers. I've found that easing with a heated caul can open a tight mortise 
about 6-10 thousandths of an inch, if more than that is needed than 
rebushing is needed. Bush samples and evaluate before bushing the entire 
set.

What makes a good stable and functional mortise? Consistent mortise width, 
uniform cloth thickness and consistency, the right amount of glue, stable 
environment, and to a lesser extent pin width consistency. In a new keyboard 
the only thing that should not be guaranteed is the stable environment.

Modern  CNC machining of mortises is accurate to within 1 thousandth of an 
inch, I have not found good cloth to fluctuate more than about 5 thousandths 
within a strip and if it does, toss it or group it with others of the same 
thickness. Poor quality cloth can be a real problem, there is some bushing 
cloth on lesser quality pianos and in some supply houses that is more like a 
felt than a cloth. This material is very susceptible to moisture changes and 
closes up a mortise tight, there is no solution but to replace it. These 
same lesser quality pianos usually also have poorly and inconsistently 
machined mortises which further complicates the problem.

Eliminate as many variables as possible and more consistency and stability 
can be achieved. Button stock, if their not accurate don't use them your 
asking for trouble, buy the best most expensive cloth, there's no savings 
with the cheap stuff. Ask questions.

Concerning balance holes, we have used maple inserts and shoes around the 
balance pin on new keyboards and have not heard back from a client with any 
problems, that does not mean there aren't any or won't be any,  I just have 
not heard of any. We have been using poplar as a replacement balance hole 
material and again, no problems reported. I guess time will tell.

Most manufacturers (I don't want to mention names) are using hardwoods for 
the buttons and balance holes now, I'd like to think that they've done the 
research and that these materials are the way to go but it does not always 
work that way.
I really did not want to open up this can of worms.    Mike

Blackstone Valley Piano
76 Sutton Street
Uxbridge, MA 01569
www.pianoandorgankeys.com



----- Original Message ----- 
From: "jimialeggio" <jimialeggio at gmail.com>
To: <pianotech at ptg.org>
Sent: Tuesday, January 04, 2011 12:57 PM
Subject: Re: [pianotech] key making specs


>
>> On 1/3/2011 7:13 PM, Mike Morvan wrote:
>>> Having said that, it gets
>>> real confusing as to what is trying to be accomplished and why. Quality
>>> and longevity? Cost? Ease of manufacture? Who knows, but I do know this:
>>> What causes
>>
>> This, the missing part, is what might be useful. Mike?
>> Ron N
>>
> Geez Mike, you can't leave this hanging...
>
> Jim I
>
> -- 
> Jim Ialeggio
> grandpianosolutions.com
> 978- 425-9026
> Shirley, MA
>
>