shank strike weights

[Ric Brekne]

Hi Folks

Now hers a thought I havent come across before.  Have to chew on it for 
a bit.  That said, Jon Page covered things in his usual knowledgeble 
fashion.  For my own part, I find that often as not you can create a 
very smooth SW curve for the assembled hammers and shanks by matching 
shanks to hammers.  Not much manipulation is needed after gluing unless 
you want the SW curve as a whole heavier or lighter.  As far as leverage 
variances due to knuckle size and the like, I usually save that for the 
last bit of hammer replacement job.  Thats because if you already have 
matched FW's to SW's, then any significant variances in BW are 
reflective of variances in the ratio... i.e. knuckle placement/size... 
capstan placement... even balance rail variance. 

How to do it ?? 

-- First weigh off all the hammers dead weight, and then the shank SW 
weights marking each peice as you go.
-- Enter your desired SW curve figures in a spreadsheet and the hammer 
dead weights.
-- Get your  spreadsheet to subtract the deadweights from the target SW 
curve figures and place the results in a third column
       (these then are whats needed in shank strike wieght to match the 
targer SW curve exactly)
-- Do a numbered sort of the resulting set of numbers and of the hammer 
dead weights.
    (That way you know for any given shank and hammer exactly how many 
are heavier and how many are lighter.)

Match as needed,  usually I end up more or less putting the heaviest 
hammers together with the lightest shanks...  I am working on a 
spreadsheet that does all this automatically and will make that 
available when I get it done. In the meantime maybe someone else might 
supply one ??

The last set I just did ended up very close to a 3/4 medium curve. The 
only weight I ended up having to add was in the form of a thicker glue 
collar around the shank.  There were two sections that were just a bit 
heavier then needed... none ended up more then 0.4 grams heavy and that 
was dead easy to take off with moderate tail shaping.

I'm thinking in the future of having 3 or 4 sets of shanks weighed and 
available when I change a of hammers.  That way I can make a near 
perfect match every time. 

Cheers
RicB






David M. Porritt writes

I understand the different heights of the knuckles and the effect on the
leverage.  Do you also find much disparity in the knuckle placement -
i.e. are all 17mm knuckles exactly that far from the center pin or do
you get a range?  That could also make quite a difference.


David M. Porritt