Roger action Geometry

[Roger Jolly]

>Hi Roger... thanks for the info... I was wondering if this piano had the
>problem with excessive action noise. In my case it was largely coming from
the
>whippen blubbering on the capstan. I didnt get a chance to do anything
>permanant about it, but I checked with some temporary front weighting and
>easing of the assist springs, and that erased the problem.
  
Hi Richard,
                 Since the springs are only supporting 5-10gms it stops
that wip bounce, before when they were supporting 30-35gms, and noisy.
Changed the jack spoon felt buttons,  (nice soft red type) also a big
reduction in noise. 
The tails were 1 1/8" from the bore centre and the hammer rail had to be
set too close to the shanks to prevent the tail from ticking on the spring
on a forte blow.  After tailing they were cut down to 7/8'' on the band
saw. The hammer rail was then set at a hammer shanks thickness below the
shanks.   another little noise reducer.

Gina and I have some good photos in upcoming Journals re tailing.
>
>I imagine tho that there were some geometric problems with that as well...
>grin.. will get a chance to check it out again next year me thinks..
>
>I will start a Petrof grand next week at the University here. This ones going
>to be interesting.. Hammers been replaced and the bore lenght is wrong. I am
>pretty sure they are short, and I think I am going to find the spread is too
>tight. Drop screws are too high and grate against the sticker as you bring
the
>action in and out. Rollers are really flat indicating jack is digging.
Wouldnt
>be a bit suprised to find this thing is really mucked up. I'll be taking a
>bunch of Stanwood type measurements as well and posting them in case anyones
>interested.

Unless you get hammer mass, bore, rake, and tailing correct, it's a futile
exercise to start a serious weight off.  Solve the strike point/ over/under
centering first, then work down wards.
Knuckle/jack alignment and positioning. A 1mm change here will alter the
touch weigh and dip dramatically.
Now check to see how much dip is required for full operation.
Next the magic line at half dip. For capstan,flange, and wip cushion center
position.
Having both the Renner and Abel spare parts kits, is invaluable to help in
the initial analysis.
I save and bore, the spare hammers from various sets of hammers so that I
can bend the back check out of the way on #1, first tenor, and #44.  Dry
hang the hammer at various weights then do the DW/UW measurements. as you
increase hammer mass 1gm, a rough rule of thumb for DW is 5gms.  Most times
just selecting the right hammers for the job can save a lot of extra work.
This will give you a lot of clues on how to proceed.
Not every job is the full meal deal unfortunately, but the more you work
with analysis, the more intellegent your decision making will be.
Regards Roger

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