LIP RIPPER
44 posts
Apr 08, 2009
10:48 AM
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Okay, I've been working on my "A" harp. I have been tweaking on this for a while. I have embossed both plates and made the gap adjustments and have really brought the harp along. It's way better than it was out of the box but I wanted to improve the responsiveness of the 1 and 2 blow reeds a little more. I worked the 2 out but the 1 just seemed a little too slow so I embossed again and played with the reed arch and gap. Once it seemed right I bolted the plates together and it played fine. I then attached the cover plates and the 1 blow quit. I loosened the cover bolt on that end and it came back. I took the harp apart and everything looked right. there was moisture from testing it so I thought that maybe I had moisture between the comb and the plate causing a hydraulic stress so I let everything dry, put it back together and it still kills the 1 blow when I tighten the bolt on that end. the plates are straight and I am careful to not over torque the screws when assembling. Any idea's?
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jbone
45 posts
Apr 09, 2009
3:42 AM
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maybe tightening the cover plate screw on the left end changes the shape of the plate just enough, and the clearance after embossing is so close, that the reed is hitting the side of the slot when you blow. there is something going on with the relationship between reed plate, comb, and cover at any rate.
not being a harp tweaker, but having experience in similar fields, that sounds like the issue. can you "un" emboss the slot a bit?
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Zhin
189 posts
Apr 09, 2009
3:58 AM
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jbone could be right.
It seems that you may be over-tightening the screws. You should only tighten them with regular finger strengh.. don't even use your wrist or arm action to tighten them or it'll get too tight. I learned that myself after experiencing similar issues when I first learned to open up my harps.
The other possibility is that you've gapped the blow reed too close to the reed plate. I suggest you examine the gapping more because I suspect either the reed may have a point that's dipping into the reedplate slot OR you've gapped the entire reed itself too close to the slot. I'm betting on the latter.
Here's a tip... the lower hole reeds that are usually thicker... they require a slightly more open gap compared to the thin reeds.
Best way to figure out how much is too much (or little) is to actually test the reed frequently while gapping until it responds just the right amount you want.
Hope this helps and good luck!
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My Videos
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gene
166 posts
Apr 09, 2009
4:04 AM
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DO NOT FOLLOW THIS SUGGESTION...I'm just guessing before Chris answers:
Since you've embossed the plate, maybe you can gap the reed lower than you have it now and that might solve the problem.
Oh, and check for burrs.
Chris, am I right, or should I sit down and shut up? :D
Lip Ripper: Thanks for abandoning the all caps thing.
Last Edited by on Apr 09, 2009 4:06 AM
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LIP RIPPER
76 posts
Jul 11, 2009
4:30 AM
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A follow up. After watching Elk Rivers video I opened my "A" harp up and using a .002 feelers gauge I discovered that I had several mis-aligned reeds. 2 on the draw plate and 3 on the blow plate. After properly aligning the reeds I was able to finish the embossing and the harp is much better. Thank you for the insight ERH.
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Buddha
805 posts
Jul 11, 2009
5:34 AM
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sorry that I didn't see this thread sooner or I would have responded.
Did you move the reeds or do they appear misaligned from the embossing?
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LIP RIPPER
77 posts
Jul 11, 2009
6:22 AM
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My guess is that by tightening up the tolerences by embossing it revealed the slight mis-alignment. The mis-alignment was uniform too. They all rubbed on the left side of the reed.
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Buddha
808 posts
Jul 11, 2009
6:54 AM
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hmmmm.... my guess is your embossing skills or the way you were looking the reed. Generally whole reeds are shifted but sometimes the tips will point one way or another.
What are you using to emboss?
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LIP RIPPER
78 posts
Jul 11, 2009
7:13 AM
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It indeed was at the tip. I am using a socket and a disposable surgical scalpel for the corners.
I wondered at first if I was putting more pressure on on side than the other and it well may be the case but I've done 17 harps now and it's only this harp that I've had such trouble. This has been a tough harp to bring into shape.
By the way, I watched your embossing vid on that same thread and the knife in the corners does make a difference. I've gone back over 4 or 5 now. Thank you for the insight.
My Harp Done Yet? :>}
I know, it's not my birthday yet.
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ElkRiverHarmonicas
93 posts
Jul 11, 2009
7:21 AM
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I'm glad you got it under control!
A reed will be slightly out of alignment straight from the factory, especially Seydels, which are made entirely by hand and you've got some young lady turning that reed so that it swings free through the slot. It can be very slightly cockeyed and work absolutely fine and dandy until you emboss it.
TO explain for the other folks how it works:
It's no big deal, you can feel alignment with a .002 inch shim.
Run the shim down one side of the reedslot, then the other. At what point down the reed does it start to feel tight? If that point is higher on one side than the other, it's out of alignment. You can keep running the shim gently down a little bit to scoot over the reed, then plink.
Last Edited by on Jul 11, 2009 7:23 AM
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GermanHarpist
465 posts
Jul 11, 2009
7:23 AM
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buddha, "...sometimes the tips will point one way or another. "
Is it possible, that this will make the overblows squeak (even more)?
Would make sense, if this would very much channel the airstream irregularly sideways instead of out the front... and thus lead to torsional vibrations.
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germanharpist, harpfriends on Youtube
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Buddha
809 posts
Jul 11, 2009
7:50 AM
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the slots need the be as straight as possible because you want to control the air flow which means channel it to the tip.
LILRIPPER, no the harp isn't finished. It hasn't even been started. Well I cut the comb and started sanding it flat but haven't done anything else yet. It takes several hours to sand each comb to perfect flatness.
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ElkRiverHarmonicas
94 posts
Jul 12, 2009
6:53 AM
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Eugene (Jim) made an interesting post on this topic of embossing and reedplate curve yesterday in the Elk forum:
http://elkriverharmonicas.smfforfree3.com/index.php/topic,155.0.html
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Tryharp
241 posts
Jul 12, 2009
7:29 AM
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Interesting post there Dave.
Buddah- Why does it take several hours to sand a comb to perfect flatness? Seems like a long time to do that, I would have guessed several minutes.
Tryharp
Last Edited by on Jul 12, 2009 7:32 AM
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Buddha
812 posts
Jul 12, 2009
7:59 AM
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because I demand precision flatness. If you are only a taking a few minutes and using your hands with any pressure at all then I can guarantee you it's not going to be precisely flat.
When you have to objects that are truely flat it create a vacuum between the side that are touching.
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ElkRiverHarmonicas
95 posts
Jul 12, 2009
8:40 AM
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Flatness is a very good thing. IMO, more important than embossing.
Interesting thing is reedplates aren't flat, either, when the slots are punched out, the plates are slightly distorted.
Last Edited by on Jul 12, 2009 8:42 AM
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Tryharp
243 posts
Jul 12, 2009
8:51 AM
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Dave,
Interesting point.
Tryharp
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Buddha
813 posts
Jul 12, 2009
8:53 AM
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Tryharp, I do it manually on precision flat plate steel. The place where I got my milling machine made it for me and it's flat to within .0001 tolerances.
'Nuff said.
Last Edited by on Jul 12, 2009 8:54 AM
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Kingley
217 posts
Jul 12, 2009
9:19 AM
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I agree with Dave.
Flatness is very important.
If you get a comb and plates flat and fitting together properly. A lot of the time you will only need to do some gapping to get a really good playing harp.
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LIP RIPPER
79 posts
Jul 12, 2009
5:08 PM
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Did I tell ya'll we're goin to see Satan & Adam tuesday??? Can't effin Wait. :>}
LR
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Tryharp
244 posts
Jul 12, 2009
6:11 PM
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LR
Awesome, I'm Jealous.
Tryharp
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