This video shows the method that I use. I've seen recommendations for using plastic covered pliers and such, but I never had any luck with that. Cover opening starts about 8:00. My favorite part of this video is when he's like" yes I'm going to hit it with a hammer". It actually works really well.
There is a special kind of plier/clip that will let you bend it all in one go, but I don't remember the name of it. Pliers will work in a pinch, but they do make it look a little messy. Functionally they get the job done though. NODs method probably works fine too, since he's doing all the banging on the part that folds under.
I have a piece of 1/4" thick sheet rubber that I've cemented to a piece of cold rolled steel bar about 1/2" x 3" x 16" (many uses!). I lay the curved up flange down on the edge of the rubber sheet, angled down so that the flange is flat against the rubber, just like this dude. Then I use a hammer with a plastic head on one side and a rubber one on the other (available a hardware stores).
Starting in the center of the protruding lip, tap gently with the hammer. I find the plastic head the more effective than the rubber one. Don't tap the lip flat in one one blow - that will leave dents on the lip. Instead, go back and forth, center to outside, using light taps until the lip is flat against the flange. I flatten mine all the way to the outside so that the tabs that stick up at the outer aspects of the lip are also flat against the inside of the flange. Repeat on the other cover plate and you're good to go. The lip will lie perfectly flat against the angled flange and there will be no dents or scratches on the inside or the outside. Works for me every time and takes a good 2 minutes.
I won't comment on the effect of doing this, if any at all. I really can't tell if this makes the harps louder or affects their tone in any way. It probably weakens the cover plates and makes them easier to crush. But it definitely looks cool and other harpers will know you're hip. 8^)
As always, give it a try on some old plates first...
Michelle
---------- SilverWing Leather - Custom leather creations for musicians and other eccentrics.
I suspect it may change the sound you perceive, while playing, by only a tiny amount. But I do not believe your listeners will hear any difference whatsoever.
Last Edited by A440 on Dec 30, 2015 11:34 AM
I've been thinking of opening up my harp covers a bit with a Dremel grinder . Maybe leave some of the lip for strength but shorten it up for a more open back . Anyone gone that route yet ?
For my Marine Bands I use two pieces of 1x and a bench vise. There not prefect if you really inspect em. But they look good that way and i believe it does make them sound a bit louder and cleaner.
I considered the dremil route with one of my session steels because they re shaped different and im not sure the vise would work as well. I'm sure they would turn out ok. Like u said leave a lil lip and then hit it with a wire wheel to round of the edge.
Also it may be a good idea to leave the rear corners alone on the sp20 because of the way they re supported. I'm thinking of trying it on my sp20 with a vise by cutting a slot about 1/8" off each corner so it leaves them unbent. And making a support post for the covers in the middle. An idea Stolen from sugar caines designs. His Harps look good. ---------- "Trust Those Who Seek The Truth... Doubt Those Who Say They Have Found It."
Last Edited by Killa_Hertz on Jan 01, 2016 12:50 PM
Halffast, it probably would work okay, as long as the harp in question has good crush support (Sp20s have that nice ridge thing on the back). When you fold it over you thicken it a bit which reinforces it.
Killa, I haven't noticed Sugar Cain's supports in particular (I've seen pics of some of his harps, they do look nice.) but the customizers have been doing support posts forever. Every harp I've seen either has a large folded piece to give it extra support or a crush post.
Nacoran sugar caines where the first ones I had seen like that, so that's whyi said it came from him. But if you check his site. .he does a thing he calls a roll cage mod,which is like a roll over support kind of like you were saying. Except i think he puts a bar inside before he rolls back the lip, I'm not exactly sure. And he does the metal Center post for support. It also just looks cool.
I like the way he shapes some of his combs too. The bad to the bone harp he does is tough lookin. I've yet to buy any of em, but i want one. There not bad on price either. ---------- "Trust Those Who Seek The Truth... Doubt Those Who Say They Have Found It."
Last Edited by Killa_Hertz on Jan 01, 2016 2:57 PM
Customizers on both the Sp20 and the MB always open the back of the covers up because it does two things, increases volume and projection. Whenever you do ANYTHING that increases the volume, such as flat sanding a comb, tightening reed slot tolerances, or opening the covers more, along with the volume comes the brightness and the only real way to fight the brightness is to learn to NOT play so damned hard all the time. ---------- Sincerely, Barbeque Bob Maglinte Boston, MA http://www.barbequebob.com CD available at http://www.cdbaby.com/cd/bbmaglinte
Like anything else, doing certain jobs are much easier if you have the right tools. If all you want to do is modify one set of covers or work on one harp, then using a hammer or some sort of homemade tool will be “good enough”. However, if you plan to work on a lot of harps – your own or perhaps as a service for others – it pays to invest in some good tools. The right tools enable you to do the job – whatever the job is – faster, better and more consistently.
Sheet Metal Seamers are the way to go for opening covers. You can buy them at Home Depot, Lowe’s or Harbor Freight in the U.S. I’m not sure where our international friends can find them but it is a safe bet that an internet search will point you in the right direction. The standard Seamer is ideal for opening Marine Band covers. It literally takes about 3 seconds to do each cover and they are perfect every time.
If you click on this picture you can scroll through a series of photos I have posted.
However, the OP’s question was about Special 20 covers. The Wiss Seamer above will not work on Special 20 covers because they are curved. So I had a set of Seamers modified to fit the SP20.
They work perfectly on the Special 20. Some have suggested keeping the tabs at the end of the covers. Some remove them. That’s a matter of personal preference. I prefer to remove them and then add a cover brace to my harps.
One last thing. The Wiss Seamer in the first picture is also the ideal tool for shaping the front edge of the covers. Sometimes you have to bend them in a little to get them to line up with the slot in the reed plate. On lower keys, if you have some reed rattle on the 1 and/or 2 draw, you need to make the bottom cover sit a little taller to give the reeds some extra room to swing. The Seamer enables you to make a modification that bends the entire cover so you can still keep the edge straight. When you bend covers with pliers you wind up with a wavy line that is not straight. For anyone who is serious about working on harps, these sort of tools are a must. And they are not expensive.
---------- Tom Halchak www.BlueMoonHarmonicas.com
Last Edited by florida-trader on Jan 04, 2016 8:47 AM
I use a Nylon hammer and a block of wood (or a proper hockey puck). The Nylon hammer can make a very clean seam. On a harp like the Golden Melody, if I want the opened lip to spread outwards like a fish-mouth, I start it off with a metal hammer and then work the covers out.
I sanded down one segment of the radius of a hockey puck and I use it to give the bent covers a little curve when needed. Be careful, if you overdo it, you will create a fold or a bow on the other side of the plate and it won't sit flush = disaster!
Duh! ... a seamer ... how obvious. Cant believe i didn't think of that. It's literally made for it.
Tom that SP20 is butter. Looks great. What do you use to make your center posts.
I just got my MB comb in lava from u yesterday. Can't wait to put it on. It's beautiful. The colors in it are somethin else. Web pics don't do it justice.
Edit: Even the vise method I use creates a slightly wavy line, even though it flattens in one motion. Not sure why, but it does. ---------- "Trust Those Who Seek The Truth... Doubt Those Who Say They Have Found It."
Last Edited by Killa_Hertz on Jan 04, 2016 1:06 PM
One thing I have to disagree on here is Nate's claim that folding the cover flanges over strengthens the cover plates.
No so. The right-angle flanges have the effect of thickening the plates. This is why engineers use I-beams to support structures like bridges and skyscrapers. I-beams afford the strength of square beams at a fraction of their weight (and cost).
When you flatten the flanges, you effectively make them thinner and more susceptible to the right-angle forces that would crush the plates inward.
This doesn't concern me near as much with a SP20 as it does with opened Marine Band cover plates. Fortunately, SP20s have the cover plate support that is integral to the comb. Not so with MBs where there is no such support. Opened MB cover plates crush VERY easily and the removal of the "half of an I-beam" that is provided by the stock right-angle flange is why.
If you want to learn more about why what I say is true, this is a good article with illustrations and comments about sheet metal as well as I-beams.
Michelle, that's a very interesting point. What's the best angle to provide best crush-resistance versus sound projection?
I never measured, but it seems to me that the vintage Marine Bands had opened covers, but the lip was not bent all the way back.
I wondered if this provided better support. I've tried creating a lip with a greater angle on present-day MBs and my conclusion was that it's all-or-nothing.
Once you bend the lip beyond a certain point (say the point where the covers start to "look" open, maybe 40 degrees) they aren't much more crush resistant than if the lip was pressed all the way down (zero degrees). And leaving them with a greater angle than that defeats the purpose of opening them up...
"One thing I have to disagree on here is Nate's claim that folding the cover flanges over strengthens the cover plates." mlefree
Michelle, I was responding directly to Halffast who was talking about dremeling off the back. You are, of course, correct that the angled back works like an I-beam which is stronger than a folded over cover, even when the 'I-beam' doesn't run the full length like on the Marine Band- which is why everyone who folds them over adds a support column unless they are using a stock comb with a built in one. But a doubled over cover would be stronger than one that just had the back cut clear off and since he was talking about wanting to open the back I wanted to let him know that folding it over would be stronger.
That said, it would also depend on where exactly you cut off the back. You could open up a portion of the back but still leave some of the fold for extra support. Not as strong as leaving the backs closed, but depending on exactly where you cut you might or might not be as strong as bended over. But support posts are easily the way to go once you open it up.
Arzajac, I'm trying to figure out the physics on that- I can see what you are saying in my head and can see that based on my real world experience having seen things bend that that would be correct, but trying to figure out the physics- If I had to guess I'd say the crushing force, when the angle is still farther open would tend to push the piece back out towards its original position, but once it's past 45 the force to push it in would be greater than the force pushing it out and it would fold in and bend?
I can't picture the tool that would do it easily, but I suppose if you could roll it up into a roll or crimp it into an accordion shape so that it had multiple layers curled/folded over you might make it even stronger. I've noticed several models make use of an arch shape or tabs coming down to the comb (Seydel Blues Favorite or Hohner Blues Harp, GM) but while that provides good crush support if the force is coming straight down the tabs are prone to bending side to side. (The GM is a little better since it only uses one thicker middle support.) I'd imagine those designs produce a fair amount of waste metal that has to be stamped off.
Tom, that's the tool I was thinking of! Right tool for the job makes all the difference.
Killa - I use a 2-56 threaded brass rod and 2 female threaded brass stand-offs. Sometimes I make them. Sometimes I buy them. It depends on availability. I am thinking about changing from the 2-56 to 2 MM.
And thanks for the props on the Lava MB Comb. I'd love to see a picture of the harp when you're finished building it. ---------- Tom Halchak www.BlueMoonHarmonicas.com
This has turned out to be a very interesting thread!
Nate, my vintage MB plates have the flange parallel to the back of the comb, just like SP20s. As to the ideal angle, it would take someone smarter than me or some heavy-duty engineering (Finite Element Analysis) software to figure that out. Maybe STME58 would tackle that one for us.
Thanks for that very informative article, JustFuYa. Learn something every day if you keep your eyes and ears open.
The concept of an "open" seam seems more applicable to describing the flanges on original SP20 and MB plates than an I-beam. The flanges are actually more "V" shaped in cross section than right angles if you consider the upward tilt of the lip of the cover plate.
Nate (and HalfFast), I've never seen a Dremel job I liked. But maybe instead of hacking away with a Dremel, folding back to leave a little open at the seam would be a happy alternative?
From a mechanics point of view, if you consider a downward force applied perpendicularly to the top of the cover plate, the sections of sheet metal that are parallel to it are the ares that resist the resulting tensions that would bend the plate. So an I-beam would work for direct downwards forces but not so much for forces coming from other directions. The V-shape would help for those forces as well. Maybe those schmardt German engineers had that in mind in 1896?
But now in efforts to (we think) improve our harps in some way(s) we flatten the seam right against the top flange, weakening it significantly. Maybe there's a better way? Someone mentioned rolling a wire into the seam. Turns out Kinya has an article on that:
He uses a Vise-grip tool very similar to Tom's sheet metal seamer. Luckily the MB flange is flat so that he could use a straight piece of wire, unlike that of a SP20 cover plate. I looked a little into putting a rolled edge onto a curved piece of metal. There are expensive (and huge) machines called bead rollers for that. Too much for a tiny harmonica cover plate.
But this dude made his own bead roller out of bubble gum and baling wire (well, JB Weld, really). Might give you adventuresome types some ideas.
And the beat(ing) goes on. 8^)
Michelle
---------- SilverWing Leather - Custom leather creations for musicians and other eccentrics.
Last Edited by mlefree on Jan 06, 2016 12:17 PM
Now THAT is how I like my MB type covers! I use a hammer and seamers to create that eye hole effect. Now I do believe I have a metal rod to make it just that much easier. You see, I've always felt that squeazing too hard when opening MB covers makes them flat and kinda ugly.
PS. I do my SP/20s like the Harp Study vid guy.
---------- I'm out of the Biz for a while till I get over my burnout. You can try HarveyHarp or arzajac, or just look the page nacoran put together under Forum Search. .
Last Edited by MP on Jan 06, 2016 2:51 PM
Now what we need is someone with a vice that has a pressure gauge on it so we can try some experiments with crush strength.
I suspect the simple crush post is probably the strongest. I've wanted to experiment with some other options for purely aesthetic purposes. I've thought, for instance, that a piece of wire the thickness of a key ring (the good ones you have to pull apart with your fingernail to slide the key on) as a ring on the back of the harp would look pretty snazzy, but you'd have to drill a spiral hole through both plates and the comb to mount it and I can't think of a practical way to do that.
If someone had a jeweler's lathe they might be able to fancy the posts up a bit, and I can think of a few other options for more attractive posts, particularly if you were, for instance, replacing a Sp20 comb, where you already had a notch cut into the reed plates but no longer had the plastic post, but nothing that could be done in the assembly line fashion you need to make something both quality and affordable. ---------- Nate Facebook Thread Organizer (A list of all sorts of useful threads)
Nate, lacking a pressure gauge, one could easily make a simple jig that would hold the harp horizontally underneath a fingertip-sized plunger through the bottom of a vertical pipe that could be filled with sand until the cover plate crushed.
Knowing the surface area of the plunger, the weight of plunger apparatus and the sand at the crush point, such a person could easily calculate the weight per surface area required to crush any particular cover plate.
A little PVC, a chunk of wood or two and some aquarium sand and you have your custom harmonica pressure gauge.
Give 'er a try!
Michelle
---------- SilverWing Leather - Custom leather creations for musicians and other eccentrics.
Last Edited by mlefree on Jan 07, 2016 11:21 AM
