Button Spring Tensiion -- How Much Is Enough?

[ragtimer]

How much spring tension does there really need to be, that your finger has to push against when depressing a button? I'm getting a little tired (literally and figuratively) of how hard my Stagi Hayden Duet's buttons are to push.

 

Assuming that I have the nerve to pop her open and stretch the little springs to adjust their tension, is there a limit to how light I can make the tension?

 

I'd assume the absolute limit is to push very hard on the bellows with no buttons pressed, and make sure there ar no ciphers (notes sounding). Springs have to hold their pads closed against the pressure.

 

But would too loose tension also make the action sloppy or otherwise less playable?

 

Maybe I'm really asking: Do top-end concertinas have lighter button tension than the cheaper goods?

Thanks in advance for any thoughts. --Mike K.

[Richard Morse]

There's a lot more too it than just spring tension. Pivot post placement, spring location, number of winds in the barrel, size of the barrel, spring stiffness.... Stagis just aren't engineered to take much of that into account. Still, it is possible to make the action lighter without unduly affecting many of the keys.

 

The majority of vintage concertina action button pressure seems to fall in the range of 40-50 grams with some are a bit lighter than that and some a bit lower. I don't have a force tester or Stagi here at home to measure but I wouldn't be a bit surprised if the action of some of their keys is over 100 grams.

 

-- Rich --

[Robin Harrison]

Do you guys use a force tester, Rich, when you regulate the key action of your new concertinas (and what does one look like ?)

Thanks Robin

[Richard Morse]

There are many types of force testers from cheap linear spring ones to incredibly precise digital ones. The one we use for button force testing is a Wanger GDK 100. They make many capacities of this model.

 

[ragtimer]

There's a lot more too it than just spring tension. Pivot post placement, spring location, number of winds in the barrel, size of the barrel, spring stiffness.... Stagis just aren't engineered to take much of that into account. Still, it is possible to make the action lighter without unduly affecting many of the keys.

Thanks, Rich -- nice to hear from an expert (who also sold me the box)

Is there a trick to loosening the tension of a spring? I would expect to unhook it, over-stretch it by the "right" amount, and put it back. Unforch, there's no way to un-stretch a spring youv'e stretched too loose.

The majority of vintage concertina action button pressure seems to fall in the range of 40-50 grams with some are a bit lighter than that and some a bit lower. I don't have a force tester or Stagi here at home to measure but I wouldn't be a bit surprised if the action of some of their keys is over 100 grams.

-- Rich --

I figure that, in order to mass-produce an instrument at low prices, the "safe" way is to over-engineer the springs, so under no conditions will you ahve a flabby button whose note ciphers.

 

What bothers me most is the next-to-top row on the RH side, which feels much stiffer than all the rest -- probably from the shortened lever arms of the "reflex" action.

 

Also the LH side is requiring lots of force, since one typically presses 3 buttons at once for a chord. This can be hard to msuter when playing very softly. I do seem to play better overall when LOUD.

 

Don't misread me; I still love my box, but the "honeymoon" is over, after 2.5 years

--Mike K.

[Henrik Müller]

...

How much spring tension does there really need to be, that your finger has to push against when depressing a button?

...

Interesting question. When I build my concertina last year, I carried

on a long-time notion that I wanted extremely light action. These days,

I have revised my thoughts.

 

Though I can't put numbers on it, I realize that action can be too light.

I find myself referring to my rebuilt Stagi Mini (which now suffers severely from

CBD (Concertina Breathing Disorder) that it would scare of most players ).

I seem to make fewer mistakes playing on that, or rather - some mistakes I

make on the new instrument I see I can trace to the lightness of touch and

the little Stagi has harder action. This is where the numbers come in:

 

At the Bradfield Traditional Music Weekend last year, Geoff Crabb demonstrated

a very simple device that would test button action. Basically a light, wooden stick

upon which thick metal washers of well-known weight, say 5 grs each could be

added. The tip of the stick was cork (= "the finger") for "stepping" on the button.

He used two, with different weights, to do a "more-than" and "less-than" test.

Great thing.

 

/Henrik

[Chris Ghent]

Is there a trick to loosening the tension of a spring? I would expect to unhook it, over-stretch it by the "right" amount, and put it back. Unforch, there's no way to un-stretch a spring youv'e stretched too loose.

 

 

Mike, if we are talking about coil springs, and it seems you are (I have never seen inside a Stagi) its worth noting that stretching a coil spring does not change its springiness, it just changes where it delivers it. If you want to make a coil spring softer you add a coil. Or decrease the material size.

 

What bothers me most is the next-to-top row on the RH side, which feels much stiffer than all the rest -- probably from the shortened lever arms of the "reflex" action.

 

Setting the buttons on short arms to feel like the ones on a long arm is tricky. With very short levers, as in some on the accidental row of a Jeffries, there is not always room for a full length spring, as its coil will hit the pad. So a shorter spring needs to be used, and this alters the feel of the button. Also the lever movers through a greater arc than the longer levers, meaning the spring does the same. If there is any rising spring rate then it will be felt. Longer levers feel like a switch, once initial resistance is overcome they work easily. Short levers can leave you conscious of the spring.

 

When the springs are to be set light there is a threshold on how light they can be, and that is defined by the pressure needed to keep the pad on the end of the longest lever on its seat, as this is the spring with the least mechanical advantage. All others can then be set to that button weight.

 

I know some of this will not be applicable to a Stagi, but I wanted to mention the effect of stretching a spring before you did it...

 

Chris

Edited April 18, 2007 by Chris Ghent

[ragtimer]

...

How much spring tension does there really need to be, that your finger has to push against when depressing a button?

...

Interesting question. When I build my concertina last year, I carried

on a long-time notion that I wanted extremely light action. These days,

I have revised my thoughts.

 

Though I can't put numbers on it, I realize that action can be too light.

I find myself referring to my rebuilt Stagi Mini (which now suffers severely from

CBD (Concertina Breathing Disorder) that it would scare of most players ).

I seem to make fewer mistakes playing on that, or rather - some mistakes I

make on the new instrument I see I can trace to the lightness of touch and

the little Stagi has harder action. This is where the numbers come in:

I think you are refeerring to the fact that, if buttons are too light, you get a lot of un-intended "bleep" notes as your fingers slide over unwanted buttons on the way to the enxt desired button.

 

I noticed a smiliar effect when I would go from playing a pipe organ to a Hammon organ. The Hammon keyboards and pedals had such a light touch that I was forever hearing unwanted notes, jsut resting my fingers on the keys.

 

It's probably best to have to make *some* effort to make a button/key sound!

At the Bradfield Traditional Music Weekend last year, Geoff Crabb demonstrated

a very simple device that would test button action. Basically a light, wooden stick

upon which thick metal washers of well-known weight, say 5 grs each could be

added. The tip of the stick was cork (= "the finger") for "stepping" on the button.

He used two, with different weights, to do a "more-than" and "less-than" test.

Great thing. /Henrik

Sounds easy enough to make in a home workshop. Reminds me of the old phonograph pickup needle force gauges -- a simple lever that you set the needle on one end, then added pennies (or your country's smallest coin) and calibrated the weight as "between two and three coins."

Thanks, Mike K.

[Geoffrey Crabb]

Maybe of interest

 

Picture of my implements used to apply effort to concertina buttons. The stand is optional and not used during use of the tools.

 

 

Two tools, a 'no go' (red band) and a 'go' (green band), are used to attain uniform button resitance.

 

Here is a diagram of the make up, poor quality I am afraid.

 

 

With an end box detached from the instrument and laid on a flat surface with the buttons vertical, each tool is gripped by the tube and the cup lowered onto a button. The lever spring may then be adjusted so the button either resists the 'no go' tool or yields to the 'go' tool.

 

The number of weights (washers) used depend on the resitance of the buttons required.

 

I will not comment on a correct button resistance as the effcts of light tension have been covered.

 

Geoff

[Bruce McCaskey]

Speaking strictly from a player perspective, I think the key element for spring pressure is that you want to be certain that the pad closes off the air flow quickly and completely after you release the button, but there's no need for too much more operating force beyond that. Perhaps fast closing is less an issue with some forms of music, but it’s essential when playing fast ornaments on Irish tunes.

 

Beyond that you want to have all buttons require about the same amount of force to operate. As noted prior, different lever arm lengths require different spring force to offer equal operating force at the buttons. Regardless of the mechanics of the process, uneven button force requirements can make playing fast multi-button sequences difficult.

 

It may not be an issue for the instrument you mention, but for bushed instruments additional spring force may be required for proper action, especially when they are first bushed as opposed to having been in use for some years, and also changes in humidity can affect the bushing pressure/friction against the buttons. I've seen newer wooden ended Dippers that had a tendency for some of their buttons to stick down after the instruments were first relocated between low and high humidity environments.

 

My Edgleys require very little button pressure yet the action is crisp, while my Dipper Clare takes noticeable more pressure to operate its buttons. If I've played the Edgleys for some days and then switch to the Dipper, I often find myself failing to press hard enough to get any sound out of the instrument on fast ornamentation. Of course my fingers eventually re-program to increase the force I apply, but it's sometimes takes several minutes before I can be sure I'm going to automatically apply sufficient pressure to sound all intended tones reliably.

 

Also as others have noted, light spring pressure can result in unintentional sounding of tones when unused fingers drift over them while others are engaged in playing. I have to watch for that when first going from the Dipper to my Edgleys. Light pressure that won't begin to depress the Dipper's buttons will move buttons on my Edgleys. Aside from increasing spring forces, one cure for that is to be more aware of what one does with the fingers not used at any given moment and certainly not to rest them directly on buttons as I tend to do when playing the Dipper.

Edited April 19, 2007 by Bruce McCaskey

[JimLucas]

My Edgleys require very little button pressure yet the action is crisp, while my Dipper Clare takes noticeable more pressure to operate its buttons. If I've played the Edgleys for some days and then switch to the Dipper, I often find myself failing to press hard enough to get any sound out of the instrument on fast ornamentation. Of course my fingers eventually re-program to increase the force I apply, but it's sometimes takes several minutes before I can be sure I'm going to automatically apply sufficient pressure to sound all intended tones reliably.

Is it just the buttons?

I find that differences in reed response and even bellows stiffness can require a similar adjustment. Switching to an instrument with less responsive reeds or simply a stiffer bellows, I find that at first notes may be weak or even silent... until I adjust to pushing and pulling the bellows more strongly.

 

Also as others have noted, light spring pressure can result in unintentional sounding of tones when unused fingers drift over them while others are engaged in playing.

Also noted, a too-light spring can result in the pad being forced open by bellows pressure alone, resulting in an unwanted note on the push (but not on the pull), even with no finger touching the button.

[Bruce McCaskey]

Is it just the buttons?

I find that differences in reed response and even bellows stiffness can require a similar adjustment. Switching to an instrument with less responsive reeds or simply a stiffer bellows, I find that at first notes may be weak or even silent... until I adjust to pushing and pulling the bellows more strongly.

No Jim, as you suggest I find there are three principal items in my mind - the button pressure, the bellows force/action required to get the desired sound, and the responsiveness of the reeds. The latter of course involves coordination of bellows motion and the timing/duration of finger pressure on buttons. Some instrument's reeds respond almost instantly to a very brief lift of the pads at low and moderate bellows pressure while others require the pads be raised a bit longer - and some may never respond quick enough to deliver the desired sound. I've played some Wheatstones that required both considerable bellows force as well as somewhat-lingering button action to get the sound I wanted, though I don't know that the ones I tried were representative of the make.

 

The bellows resistance to movement with the air button open seems quite low in all three makes of concertina I own, but there's no doubt the Dipper Clare requires more bellows effort than my others to sound the reeds properly. So much so that I've played it very little in the last few months since developing a shoulder issue at the start of the year. I used to play the Dipper several hours each day without noting any problems, but now find twenty minutes with it is too much. On the other hand, I can play one of the Edgleys or the Tedrow for an hour or more before feeling the need to quit. One shouldn't take from this statement that the Dipper is hard to play, rather just that the Edgleys and Tedrow require less bellows effort and my shoulder is rather sensitive still.