Installing grand backchecks

[Roger Jolly]

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Hi Graeme,
                  Check height,  with the hammer set at the desired blow
distance, the centre line of the shank should line up with the top 1/3rd point
og the check. With the rake set at 22  degrees, and a radius of  the tail
being
1/2 the distance of the tail to centre pin measurement, and the tail from the
bore centre being 3/4" but no longer than 1". every thing will regulate just
fine.
See this months Journal, east to read pictures.
Regards Roger



At 07:44 PM 30/08/00 +1200, you wrote: 
>
>  
> Willem wrote....
>  
> <Greame. I guess I'll have to say it again: Fly me down there, and I'll
show 
> you. :)
>
> <To remove and install back checks, with wires, I find it works best if you 
> put the key in a vice. Remove the wire with a pair of side cutters, but
use a
>
> small block of wood as the fulcrum point, instead of the key itself. This 
> will pull the wire out much easier and it won't elongate the hole. . 
>
> To install the new backcheck, I use a soft face hammer to gently tap the
new 
> wire back in. As far as height, measure the old one, and use a jig of some 
> sort, (a hammershank with a line on it) to determine the correct height of 
> the new one. >
>  
>  
> Hi Willem, 
> You could fly down and do both jobs at once (valuing pianos from a previous
> enquiry). :)
> In this particular case, though you are probably not going to get here on
> time, as I hope to complete this job in a few days.
>  
> The new checks I've been supplied with are fitted to the wires already, and
> my query was how to install them complete without removing the wires. Is
your
> method, using a soft faced hammer intended to tap the top of the check
itself
> or just the wire?
> How do some of you others approach this?
>  
> The other issue of check height relates to a re-designed action, lowered
> hammer centre height etc etc, so the old check height may not be the best
> position, though could be a close guide. Sorry I didn't mention this before.
> (Pity, you could've stayed a bit longer in NZ to solve this one too)
>  
> My thinking is that for the most efficient checking, the best situation
is to
> have the most hammer tail surface area in contact.
> Therefore, if the ideal checking distance is say, 16 mm from the string then
> the top of the check could be set so tat the hammer tail is well down the
> check leather.
>  
> Does this make sense?
> Any other thoughts on this, any rules of thumb (or rule of thumbs) here?
>  
> Regards
>  
> Graeme Harvey
> New Plymouth 
> New Zealand
>
>
>  



Roger Jolly
Saskatoon, Canada.
306-665-0213
Fax 652-0505 
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