On Mon, 28 May 2007 10:23:25 +0800, Brooke, Doug (Elite) wrote:
snip
> I have solved the problem by installing "staples" in the back of each
> jack a-la KIRCKMAN (nota bene sp - peter!) and the problem is solved,
> they work flawlessly. 

My own exerience founded opinion is that a jack that needs  a staple is 
a bad design. 
I am not the only buider how thinks/knows this and not the only one on 
this list.

> The other possible solution would be to increase the strength of the
> bristle to resist the tongue

the only "real" solution where everything else is right.

snip
> it sounds like a recipe for hangers and that we
> ought to try for the lightest possible spring that will do the job- ie
> facilitate rapid repitition.

that is not acco,mplished by a weak spring and anyway, lots of other 
things are more important. 
Things such as flyback control and touch control. Where a staple and 
weak spring are used, 
touch control is not possible at all. 

> Then there's the issue of possible clicks - on the one hand the click of
> tongue against staple 
 obviously a self-induced problem not present with a good design.

> and on the other the click of tongue against the
> bottom of the slot as it comes back home, or I guess the worst of both
> worlds two clicks.  I haven't installed "anti-click" pads anywhere and
> to my ears they aren't required:  

exactly: they are not required.

admittedly some jacks click quite loudly. This, too, is a design 
problem, not one of padding or weak springs.

THere is presumably quite a bit on the subject in the archives.

let me quote just this:
>Speaking for myself, but I think Mike agrees, I have found that the 
bristle should contact the tongue quite close to the axle and rest in 
the groove for a good length and be quite strong. There is more control 
and higher damping of tongue movement = less flyback. Neither of us use 
any kind of flyback control on the jacks now.
snip
>2)get down to brass tacks and do it, refine and keep refining, 
analyzing what causes which and what is important musically. Absolutely 
reliably falling jacks are not at the top of that list. That is not to 
be confused with repetition and I know Mike is not confusing that issue.
And it is absolutely necessary to have top-notch players like Kris 
Verhelst "testdrive." To listen to what they have to say about dynamics 
and touch response. 
One thing is for certian: touch response and flyback control are two 
sides of the same coin: you can't have one without the other. needing a 
string or staple just demonstrates the lack of control, both 
technically and musically.<

b


PS: a shooting board to trim endgrain looks like this:

http://www.zabernet.de/bill/Jackmaking_pics/dressing%20endgrain.jpg

It is a very basic cabinetmaker's tool.