Melodeon.net Forums
Discussions => Instrument Design, Construction and Repair => Topic started by: mselic on October 21, 2018, 05:25:24 AM
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I've been experimenting with coil springs on the button levers in the keyboard mechanisms of one-rows. The stiffness of a spring can easily be reduced by prying between the coils with something like a flat-head screwdriver, and the same springs can then be tightened back up again by holding each end the spring with pliers and twisting it back in on itself (yes, I realize that doing this over and over again isn't ideal for the life of a spring, but I'm experimenting...) This has allowed me to try out what different spring tension feels like on the buttons and how it relates to keyboard action. I can make them have a very light touch or a rather stiff feel, and everything in between. I've found that if you go too soft, the actions isn't quite as "crisp", whereas if they are too hard, well, that's just more work...there is usually a happy medium.
What I'm wondering about is this: let's say I get a particular set of springs, of a particular diameter with x number of coils, and I set them up to get a certain amount of tension on the buttons that I like. If i get a different set of springs, made from a different diameter and with a different number of coils, and I set them up to get a similar amount of tension, will the end result be the same? Or would the feel of the springs be different, even if they have been set up to achieve the same amount of tension? I ask this because I've noticed just how different coils springs and button action can feel from one instrument to another of similar design/dimensions. I'm wondering if the size/shape/etc of the springs makes any real difference there, or if they are simply enacting a particular amount of tension/force regardless of those factors. I'm hoping my question makes sense...
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For the sake of consistency I would experiment with making them from scratch. The variables would be wire material and diameter and number of turns. If is quite easy to make a winding tool.
Tiposx
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I would say the spring with larger wire and/or smaller diameter coil will apply more "come back home" force as it gets stretched further.
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Here's an update, for those that it may interest: I experimented with larger coil springs (springs with both a larger wire and larger coil diameter) and I managed to get a very light touch on the buttons but still retain the "snappiness" that I desired on the one-row. So to answer my own question, differently sized springs will behave differently even if they have been adjusted to both require the same amount of pressure to lift the pallet off the board. The smaller springs allowed the pallets to lift easily, but were somewhat sluggish in their return, resulting in what I would describe as "mushy" playing. The larger springs allowed the pallets to lift just as easily, but their return was quicker and more immediate, resulting in a crisper sound and feel.
I realize for some this may all sound like obsessing over minute details, but for me it completely transformed my instrument! I am happy that I was able to replicate on my own instrument the feel and action of keyboards that I liked in others. Anyhow, information to share for those who care!
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"Here's an update, for those that it may interest:"
It certainly interests me, as far as I'm concerned this type of posting is a main part of why I love this site. Thanks mselic, and keep them coming!
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Did you ever experiment with making a coil spring shorter to get more tension ?
I’m thinking of ways to make my one row a bit tighter, I don’t see how I could or can spread the nails future apart with out being to close to the edges, if I wanted to go that route ( I don’t). Wondering if its easy enough to take out a coil or two of the end and rebend the loop?
Wish I had an extra to experiment with.
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Yes cut off a coil and bend a new loop.
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Yes cut off a coil and bend a new loop.
Thank you Theo, I’ll give it a go
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Yes, cutting off a coil as Theo has described is the way to go. If you’re not happy with the results, you can then also begin experimenting with coil springs of a thicker wire gauge.
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After you have cut off the loop place the spring flat on the bench and put two thin knife blades between the first and second coil.
Push one blade away from you and with the other blade bend back until flat on the bench forming a new loop.
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this is very interesting.....i have 6 acadians and they all feel different yet they all have the same springs? so what ive been wondering is do springs age? if one accordion has 50 year old springs (one of mine has) and another has 10 year old springs ..even if they are adjusted to feel as close as possible to the same tension will the age of the spring make a difference to snapiness and smoothness across the range of button travel. Or to put it another way do springs (even if they are adjusted as good as possible) have shelf life like wax and valves. Should they be replaced after a certain life span and will this give the keyboard a fresher feel? Im no metallurgist but all that bending after 10 or 20 years is bound to change the metal in some way i guess? Id be reluctant to try and make coil springs , very fiddly and difficult to get coils uniform. In any case long coils can be obtained very cheap on ebay and cut up into coils of the desired length. But when making springs for the bass end ive found the following all make a difference....thickness of wire /number of coils /diameter of coil / length of arms /angle created by the 2 arms. there may even be a difference depending on where you buy the wire and whether it comes straight or packed in a coil. And of course ones made on friday afternoon never seem to work as well!
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Spring steel does weaken and snap. I don't think that time alone is a factor, but repeated compression/expansion/bending certainly is. Coil and leaf springs on motors give up now and then, as do spring steel reeds in our instruments.
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After you have cut off the loop place the spring flat on the bench and put two thin knife blades between the first and second coil.
Push one blade away from you and with the other blade bend back until flat on the bench forming a new loop.
Took me a few minutes of (ok now what ), after I cut the loop off but I did exactly that (:) only adding that I nailed it ( the spring ) on one end to a board, divided the coils with Swiss army at point of new bend, slipped a very thin putty knife to the side I was keeping held the coils in place and bent the loop with the knife. Cut off any extra coils if needed. I took four off mine it’s better, Worked great!! The nail in board was to keep the loop in line with new bend, plus it kinda held it as I worked the other tools.
Thanks all!
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What a coincidence! I use a Swiss Army knife and a putty knife.
Nail in board, good idea.
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this is very interesting.....i have 6 acadians and they all feel different yet they all have the same springs? so what ive been wondering is do springs age?
There may be other factors accounting for the difference (ex: spring is the same but the distance between anchor points is not). Maybe swapping springs between 2 boxes would tell you ? From my - admittedly limited - experience, springs do age and eventually break, especially if of small size or poor metal. But there are also 100-year-old boxes with original springs still going strong, so...
Simple solution to your different feel problem, Chris: give me 5 of your 6 Acadians ! After that, all your Acadians will have the same feel !!! ;)
Just kidding of course. Are they all in different keys ??
I have one in D, which had very hard snappy action, to the extent that the original owner developed hand problems and sold it. I bought it from someone else and replaced the springs because I was beginning to have problems too.
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What a coincidence! I use a Swiss Army knife and a putty knife.
Nail in board, good idea.
😄
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Are they all in different keys ??
I have one in D, which had very hard snappy action, to the extent that the original owner developed hand problems.
yes. one in D that i had made back in the 80's. another in D that was in C but i converted to D because my original D was a bit thin sounding. then i "inherited" a D from a friend who passed away. so thats 3 in D. one in G i just bought. one in C i bought in the 90's. then along came another in C that was so beat up it was almost scrap but i did a total rebuild. is that six? plus a master in C and an international in C and a globe in A and so it goes on.....i dont get hand problems any more...started on a hohner and that built up the finger strength, then moved to acadians. I used to like a heavy action but nowadays im all for a lighter action but sometimes you lose the snap.....thats why im curious about springs. i want light and fast with an easy tension with a fast return...maybe too much to ask but curiously two of my boxes have it and its hard to say why!
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My Beltuna is about 160g, the box I built is now about 140g.
Compared to this chart.
http://forum.melodeon.net/index.php/topic,23700.msg304479.html#msg304479
Edit to add correction: Beltuna after further testing on the keyboard it is really closer to 140g
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Compared to this chart.
http://forum.melodeon.net/index.php/topic,23700.msg304479.html#msg304479
This reminds me that I never measured my 'too hard' Acadian after replacing the springs with softer ones. I did just now, and it's at about 110g, half the original 220 g.
This is probably borderline-soft: still adequately fast and responsive but in agressive playing if I hit (rather than depress) a key hard, it sometimes bottoms out with an annoying wood-on-wood clacking noise. Also, pushing real hard on the bellows with no key pressed produces a soft wheezing sound: front of pallets lifting slightly and all H reeds singing together. No problem in regular play, but I plan to shorten the springs eventually.
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I had a 100 g weight and it moved/ opened the pallet quite easily on the box I made prior to adjusting to the 140g range. Now 140g just starts to open pallets.
And i had a bit air noise on the push before adjustments also.
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i like this precision. I just set one of my Acadians to 160 and it feels nice. set another to 140 and a 150 on another so i can compare. Hard to feel the difference on dry test but its evident when playing. bottoming out on acadian i remedy on mine with EVA self adhesive foam. 10 minute job with the self adhesive stuff. cut slightly narrower than the slot. I use 3mm an an acadian (5mm on a martin)...if you like buttons to go down in to fingerboard try 2mm or 1mm EVA.
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i like this precision. I just set one of my Acadians to 160 and it feels nice. set another to 140 and a 150 on another so i can compare. Hard to feel the difference on dry test but its evident when playing. bottoming out on acadian i remedy on mine with EVA self adhesive foam. 10 minute job with the self adhesive stuff. cut slightly narrower than the slot. I use 3mm an an acadian (5mm on a martin)...if you like buttons to go down in to fingerboard try 2mm or 1mm EVA.
Interested in your comparison results ,let us know.
My Beltuna has a button height of 5mm and the box I made is just under 6mm, I just lower them from whatever the maximum is using the standard button.
I find that with the normal cajun style keyboard design you can’t put enough padding to keep the buttons flush to keyboard. Mine with maximum padding while still allowing me to remove the keyboard ends up sinking in to the hole.
One reason why I’ll be doing things different on the project I’m doing now.
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Here's my keyboard design (from Emmanuel Pariselle). Easy to apply padding under levers.
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Here's my keyboard design (from Emmanuel Pariselle). Easy to apply padding under levers.
Very nice Rees, looks like what I’ve got started :D, we think alike again!!
http://forum.melodeon.net/index.php/topic,23700.msg323984.html#msg323984
Beltuna uses the exact same design but with scissor springs. I like that you can pad it easy and that you can remove the levers if needed.
I just measured my Pepperpot buttons ( which is not coil sprung ) hows under 50g for light.
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I’ve padded under the keys of all my own rows. Sometimes you have to be incredibly creative when access under the levers is limited. Rees’ design is ideal.
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I’ve padded under the keys of all my own rows. Sometimes you have to be incredibly creative when access under the levers is limited. Rees’ design is ideal.
Matt, I did pad with two strips of the red piano felt = 3mm or less. No room for more on mine with 14mm space inside, button 9mm height , lever 3mm and plus felt.
So yes, Rees’s design it is! or is it Emmanuel’s or maybe Beltuna’s ??? ;)
I used a dovetail jig i have to make a wood jig that I used to make all the cuts. Nice thing with this type dovetail jig is it is easily repeatable and accurate. I could not get the same results using my tablesaw setup, could have been my setup.
I tried Melodie’s (as seen on how it made) keyboard design but failed when routing out the pocket for the keys, got a little to close with router and knock off a leg ( piece between the lever ). Not sure what they do to tie in the legs on the back or do they not? Legs would be prone to moving if nothing was done.