Re: [Harp-L] Tension Headache

Elizabeth Hess <TrackHarpL@xxxxxxxxxxxx> · Tue, 10 May 2011 11:46:01 -0400

On May 10, 2011, at 1:25 AM, Joe Leone wrote:

On May 9, 2011, at 9:57 PM, Elizabeth Hess wrote:
<snip>

Then I got greedy and tried to get 1 overblow.  Put the harp back  
together, and couldn't get 4, 5, or 6 for nuthin'.
....  Screwed the harp back together, couldn't get them.  Backed  
the interior screws off a bit (Did I have them so tight that I was  
warping the reed plates?), but no joy.  Gapped and embossed too  
far, backed off, back and forth, stayed in denial and just tried  
for determination...   last couple of days:  bupkis.
Just now I disassembled the harp, held it together gently, and  
didn't I overblow 4, 5, and 6 as just nicely as you please.  Put on  
the

cover plates and then the
binder clips, and lost the overblow on chamber 5.  Took the clips  
back off and got it, again.  Can anyone explain what's going on,  
here, and what the remedy is?

<snip>

Your harp is suffering from ' crooked door frame syndrome'. Let me  
explain. Please.

But of course!  :-)
Imagine that you have just installed a door frame. And you are  
standing inside facing it. You measured the opening and it was 32  
1/8" (the proper amount). But what you DIDN't realize was that  
within the 4" width of the frame, there was a deviation. The INSIDE  
of the frame (the edge facing you) was 32 1/8", BUT the edge facing  
outdoors was  only 32 1/16". You wanted the door to be tight. For  
security reasons. You don't want to leave any room for someone to  
stick in a shim and jimmy your lock. But when you go to mount the  
door, it is too tight and won't fit. Why? because the cant of the  
frame has changed the dimensions that you needed. (Key: doors are  
oversized anyway with the idea that they will be finish planed).
When you had the binder clips on the ends, you made a belly ever so  
slight in the plate. Hardly descernible with the naked eye. But  
there none the less. The clips have a foot pound rating of (I'm  
guessing) 75 to 80 foot pounds. If you were to apply one to your  
finger, it would exert as much pressure as if you had your finger  
under the leg of a loaded chest of drawers.

This explanation is so lucid, even I can understand it.
So, embossing will exascerbate this problem because you were already  
working with a fairly small dimension. And now, you made it even  
smaller.

So, visualize looking at the cross section of the reed slots and you  
will find that even this slight belly in relation to the small reed  
plate can be extrapolated to the 1/16th" in relation to a full sized  
door.
Ergo, the slot is now too tight.

EXCEPT that the problem I had when I screwed the harp back together to  
"normal" tightness was that I couldn't get the blow reeds to choke.   
(And there's no way to know whether the draw reeds would have sounded  
the overblow if I  *had*  been able to get the blow reeds to choke.)   
Sorry I wasn't more clear on this point the first time.
Sooo.....  Maybe I need to emboss just a teensy bit more?
Backing off the pressure will allow the plate to flatten out enough  
just enough that the deviation disappears and you now are SQUARE in  
the slot. When I use binder clips, I sometimes put them at the BACK  
of the plates. And even if they rest on the rivets, that shouldn't  
make a difference. Now at the high end (where the reeds are short  
and leave a lot of plate), the clips can take a deeper bite thus  
spreading the load more evenly.

Hmm.  I was putting the binder clips on the whole magilla sandwich,  
cover plates and all.
The current state of affairs is that I have the reed plates  *very*   
gently screwed together, and the cover plates  *very* gently screwed  
on, and I can get 4 and 6 overblow reliably and 5 with some effort.   
It kind of violates my sense of ship-shape not to have those screws  
snug, but I understand that too much of a good thing is a bad thing,  
and it's the sound that counts.
Of course it's hard to diagnose a hardware problem via written  
correspondence.  I know that I mostly have to do this myself.  But  
your answer has been enormously helpful in identifying the relevant  
mechanics, so now I have a better idea of what's going on.  Thank you  
very much.
Elizabeth
P.S.  I used to think that practicing meant harp-in-mouth time.   
That's turning out not to be the whole story.
I refer to this as "rigging the sailboat":  If you don't enjoy rigging  
the sailboat as an activity in its own right, then sailing is not the  
hobby for you.