Richard,
I'll respond "In between the lines":
>Date: Thu, 15 Oct 1998 18:07:25 -0500
>From: "Richard Moody" <remoody@easnet.net>
>Subject:
>Hi David
>Thanks for the reply. There are a couple of things I am not clear on.
>Perhaps you have already published something I should read first before
>asking questions. So please don't hesitate to post pointers to that.
>An intersting process you mention is to " Take a note and measure
>Up/Down with different hammer flange frictions."
> I am wondering how to get those diff frictions in the same note, and how
>are they measured, ,,,,,The hammer swings so many times? or so much
>weight drops the flange?
I have a method of adjusting flange friction with set screws, otherwise repin.
Measure using a gram guage.
>When you say " Plot the results on a chart and you will see that as
>hammer flange friction friction decreases, overall friciton decreases and
Up/Down converge."
>This makes sense however there are other frictions acting on
>upweight, the wippen flange and capstan against cushion for two. Are
>these taken into account?
They stay in the mix unchanged because your only changing Hammer flange
friction in this case.
> Over all then, I am not sure how important the measurement
>of up weight is, other than to indicate more or less friction between
>notes, especially given the fact that down weight seems to be what the
>action is designed for.
Down weight and upweight are equally important as idicators of the point
around which they are centered. In other words the balance weight is the
primary indicator that we look for and find as the point in between up and
down which doesn't change with friction. The balance weight would be the
amount of weight placed on the front of the key that would balance the key
with no friction. Down weight is the balance weight plus the amount of
weight necessary to overcome friction and cause the key to go down. The
contrary is true for upweight. You have to take away weight to get the key
to go up.
So Upweight and Down weight are equally important as indicators of balance
and friction.
>My take is that friction does not change by adding or taking away weights.
> So if one considers that Dw - Uw = Fw (a quantity of friction), and this
>quantity is constant, then if Dw changes, Uw must change by the same
>amount.
Right
>So regarding "just ask them to change Up/Down on an an action model to
another of their choice. Most would fail" ............
>I would reply, you don't really get a choice. The only things you can
>change in an action are weights and friction. You can change one but then
>then you have to accept the changes in the other(s). You have to decide
>which one you want, the down weight to a certain spec, and be stuck with the
>upweight. Or vice versa. The difference between down
>weight and upweight will always be the same, unless friction changes, at
>least on paper. You can change friction but you can't predict how much
>the friction will change, you can only measure the results and live with
>that.
Not true. For every gram of hammer flange friction you'll see about a gram
change in the friction weight (Down - Up)/2.
Any up/down combination may be made by controlling weight and friction.
>> Did you read my instructionsin my recent post for accurately
>> adjusting Turbo Wips?
>> Try it. It works. That's what counts."
>I did, but I didn't understand why if you want a 51 g down weight why not
>use a 51 g weight to begin with? In the example below. The 58 Dw is high
>to begin with before any figuring or other measuring is done. So take 7g
>off Dw to get it down to 51g, should give a measured Uw a difference of 7g
>(38-7=25). which is what you also come up with. So no matter what you
>do, friction weight (Fw) if you want to call it should be, Fw = Dw - Uw.
>It's 26 with 58-32 and also 51-25 that appears below.
>You said...."For instance:
>>Up = 32
>>Down = 58
>>Friction = (58 - 32)/2 = 13
>>BW = (58 + 32)/2 = 45 (Kind of high)
>>lets lower the BW to 38:
>>New Up = 38 - 13 = 25
>>New Down = 38 + 13 = 51
>>Put a 25 gram wt on the front of the key and set the spring to lift that
>>Wt.
>>The down weight will be 51.<<<<<"
>The difference between up weight and down weight is still 26. which is
>logically where it should be, since you haven't changed friction, and you
>are measuring weight in the same place. All you did was change the spring
>to take some weight off the wippen. (and even more off if you sent it up in
>a rocket) .
The excercise here is only to fine tune the turbo wip spring not friction.
Suppose you have a key with a 58/20. You can just set the spring to make 51
down but your up weight will be 13. You have to measure balance weight and
friction weight then change whichever component is wrong.
>I don't know, but it looks like the two equations are divided by 2
>, so the shouldn't the 2's should cancel out.? The ratios are the
>same.....
Your really missing something here. Go back to thinking of a see saw with a
frictionless pivot. Lets say it takes 35 grams to balance. Now make the
pivot rusty.
Now because of the friction it takes an extra 15 grams to overcome the added
friction and make it go down. That makes a total of 50 grams. To make it
go up you have to take away 15 grams from the 35. That makes 20.
Now apply the formulas: Balance Wt = (50 + 20)/2 = 35
Frictio Wt = (50 - 20)/2 = 15
Get it?
Come to the Kansas City National Institute. I'll be doing a full day
seminar on this stuff on Weds. No extra charge.
>One final question, and If I were going to Houston, ooops that is today, I
>would look forward to attending your class. If there is a video of it I
>would rent it.....
No can do.
>You say Bw = (Dw + Uw)/2 . That looks like the average of Dw and Uw.
>And this implies also that Bw , Dw and Uw would all equal when there is
>no friction.
Right on...
>Balance weight also implies that wo friction Bw would equal
>the weight on the capstan divided by 2, when the ratio of the key lever
>is 2/1. (Bw = Cw/2) Is this what you mean by balance weight (BW ?)?
>Ric Rocket
Very Wrong.. go back to the se saw sample.
It's see saw science not Rocket Science
See you in KC
David C. Stanwood
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