Hammer re-facing and blow distance

[Farrell]

> If the 
> action is reasonably good at that distance, and it's not a top-grade piano 
> or a customer with lots of money, is it necessary to mess with packing the 
> rest rail etc?  

No, it is not necessary. A complete job would indeed include regulating blow distance, etc. But you are correct that just by filing hammers down to the base of the existing grooves, you haven't changed blow or let-off or anything else.

> A fairly quick hammer re-facing, along with tightening all 
> flange screws and taking up lost motion, can make a huge difference to the 
> sound and feel of a semi-decent old upright, at reasonable cost.

Yes. But I'm curious why you separate out regulating lost motion from the rest of regulating tasks. Just because you have filed the hammers, doesn't dictate regulating lost motion. However, I do agree that lost motion regulation on a long-neglected piano is often one of the most beneficial single regulating steps.

Everything else you've stated sounds like pretty sound thinking to me.

Terry Farrell

----- Original Message ----- 
> Yesterday I did a hammer re-facing on a client's 1929 Challen upright.
> 
> Hammer re-facing is a job I enjoy doing.  I take care to keep a proper 
> shape, and it never seems all that difficult to me, yet I have seen some 
> horrible jobs. Recently I saw a piano where the hammers were all lop-sided 
> because someone had done a very crude re-facing by filing (with I know not 
> what implement, the hammer felt looked all roughed-up) from the top side 
> only, towards and over the striking face. The hammer bottoms had not been 
> touched.
> 
> I was musing about the conventional wisdom which says that after re-facing, 
> the blow distance should be adjusted by packing felt behind the hammer rest 
> rail, and the action re-regulated.  In practice I have seldom done this 
> after re-facing.  There is the practical consideration of what the customer 
> would be willing to pay, balanced with the very substantial improvement to 
> an old piano that can be made just by re-facing.
> 
> What I was thinking, is this: If you re-face carefully, you don't increase 
> the blow distance beyond what it already is, because you only file the 
> hammers to the level of the bottom of the exisiting grooves. The existing 
> blow distance is from the bottom of the grooves to the strings.  If the 
> action is reasonably good at that distance, and it's not a top-grade piano 
> or a customer with lots of money, is it necessary to mess with packing the 
> rest rail etc?  A fairly quick hammer re-facing, along with tightening all 
> flange screws and taking up lost morion, can make a huge difference to the 
> sound and feel of a semi-decent old upright, at reasonable cost.
> 
> And in any case, adjusting the blow distance to what it originally might 
> have been, does not restore the piano to what it was, as it now has smaller 
> hammers and an altered action geometry.
> 
> Best regards,
> 
> David. 
> 
>
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