[pianotech] cold pressed hammers

[Dale Erwin]

Hi JD
  Understood.  Where does one buy ancient hammer making manuscript?

 

 

Dale S. Erwin
www.Erwinspiano.com
Custom piano restoration
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209-577-8397
209-985-0990

 

 

-----Original Message-----
From: John Delacour <JD at Pianomaker.co.uk>
To: pianotech at ptg.org
Sent: Thu, Sep 30, 2010 12:15 am
Subject: Re: [pianotech] cold pressed hammers


At 00:09 -0400 30/09/2010, Dale Erwin wrote: 
 
>Ok, I don't know where this info comes from but having my hands on a >Dolge type screw press and having participated in operating it makes >me question the numbers below as truly possible. Ok, maybe a mute >point 
 
Hello Dale, 
 
The info comes from the horse's mouth -- Alfred Dolge. 
 
By the time he published his book in 1911 he had long got rid of his screw presses and was using pneumatic machines. 
 
>>At Dolge's factory, working with animal glue, about 1910 he >>estimated that two expert gluers working on a single machine were >>able to cover 240 sets in 10 hours. This was achieved, on his >>latest machines, but also on earlier machines by other makers in >>Europe by using removable cauls. 
 
>   Ok, lets think this thru.  First cutting felt strips and preparing >them for gluing would take at least a couple days. Takes a skilled >hand and an sharp knife. And 24 sets per hour for ten hours doesn't >seem real to me. 
 
If you read my quote, or even better read his book -- I'm surprised you haven't -- you will see he is talking of the men at the machine, the gluers.  He obviously is not talking of the total time taken to make and cut up the mouldings and the time taken to cut the felt. The gluers are working with a pile of felt strips and a rotating stock of removable caul/clamp units.  I presume also that the mouldings are already clamped by another less skilled workman.  The whole point, and what we are discussing here, is machine time. 
 
>>If Dolge's men (and no doubt others, using different machines) were >>able to press hammers at a rate of one set per three minutes >>without using heated cauls, I suggest that, as in so many other >>instances in our trade, a great deal of good sense and invention >>has simply been lost over the years. 
 
>   No doubt but the numbers seem impossible without more hands in >this operation.  No what I mean? 
 
The subject of the thread is "cold pressed hammers" and the purpose of my response was to point out that the overheating of hammer-heads in order to speed up the setting of the glue is quite unnnecessary when removable clamping assemblies are used, as they were widely before the first world war, and not only by Dolge, whose word I have no reason to doubt. 
 
JD 
 
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