Action spring pressure

[SteveS]

I recently bought myself a cheap used force gauge off eBay with the intention of using it when setting up the action on my concertina repairs.

 

I ran over the buttons on an unrestored Aeola EC and the results were quite interesting - the force required to depress a button was between 60g and 100g.

Edited April 23, 2011 by SteveS

[Ardie]

I have checked some Lachenal(3) and Wheatstone (10) Englishes. The figures varied between 50g and 90g but not related to the makes. Two Case trebles were significantly lower ( 30g) but these have smaller pad holes which makes lighter spring force tolerated as less force is required to avoid leaks.

One remarkable finding is the variation within individual instruments.Any piano player would go mad if having such an uneven touch resistance. (The normally set "weight" of pianos is in the same range, 50-80g, but is usually very precise )

There are many interesting aspects on this.

- I think the (un-)evenness of spring force with concertinas is a matter that ought to be considered more since uniformity of the keyboard no doubt improves playing conditions.

- The findings so far contradicts the saying that Wheatstones have lighter springing than Lachenals (since Wheatstones use riveted action).

- Generally speaking it is intriguing whether a light touch resistance favors speed or not.

- The subjective impression from button resistance is very much related to the diameter and structure of the button.

[4to5to6]

I imagine that musical expression goes way up with even key heights, cross hole bushings that are just the right size, spring tension set even and at the right level, pads lifting to right height etc. etc.

 

At the very least it would make the instrument a true pleasure to play as all your energy is going into making the music rather than compensating for inconsistencies.

Edited October 23, 2016 by 4to5to6

[Jake Middleton-Metcalfe]

Just a thought

 

Steve did the aeola feel nice to play? I mean was this spring pressure inconsistency noticeable while playing as opposed to pressing each button consecutively with the same finger?

 

I have been wondering on this one, each finger is a different size and surely a different strength. It may be that this sort of deviation is actually not really noticeable. Or did it just feel a bit inconsistent to play?

 

Jake

[SteveS]

The concertina even severfal years later, is still relatively well balanced in the action.

I dont notice any differences due to relative finger strength.

[Don Taylor]

I recently bought myself a cheap used force gauge off eBay with the intention of using it when setting up the action on my concertina repairs.

 

Steve

 

Could you provide some details about gauge that you bought? Maybe a picture.

 

I searched eBay and could find nothing cheap that measured small forces.

 

Thx. Don.

[Alan Day]

It is interesting to note that brass age hardens and springs as a result become more brittle with age.The brass wire I had for springs was always a bit soft and lightly hitting it with a hammer along it's length hardened it up to the necessary spring tension.

Al

[BW77]

It is interesting to note that brass age hardens and springs as a result become more brittle with age.The brass wire I had for springs was always a bit soft and lightly hitting it with a hammer along it's length hardened it up to the necessary spring tension.

Al

The common metallurgy/goldsmith method to achieve the same is to "draw" a thread through a sequence of holes to smaller diameter so if you want to produce springs for concertinas from wire you choose a slightly wider thread and draw it to the wanted tension and diameter. To get the wanted spring action you can experiment with the number of loops also, depending on what character of resistance you prefer.

( Do NOT be tempted to use "lighter action" to make it faster. This is a misunderstanding. You get "faster action" of course by using as high spring tension as you can tolerate by your own muscular strength. You have the same conflicts with pianos for example. Some people intentionally exercise with high key resistance and perform publicly with less resistance (and another piano hopefully...).

[BW77]

I have been wondering on this one, each finger is a different size and surely a different strength. It may be that this sort of deviation is actually not really noticeable. Or did it just feel a bit inconsistent to play?

 

Jake

Try one instrument with as varying key pressure as it often is, even with "high quality concertinas" , just like Steve reported, and compare playing comfort with one that got a well adjusted keyboard i e with a tolerance say +/- 5 grams at most. It is rather strange that concertina players accept such variations ( also concerning button height, which may differ a lot on restored/reconditioned instruments unless attended to in particular) . The circular arrangement of the mechanism of course makes it more difficult to get an even keyboard than with the straight accordion mechanism for example.

[Dana Johnson]

It is quite possible the springing was more even originally and while some springs may have gotten weaker, others may have been tweaked in an effort to deal with leaky pads, binding levers, tight bushings etc. Most of the makers I know put some effort into getting an even button pressure usually around 50-60 grams. Keep in mind, short levers swing through more angle to lift the pad go the proper height, so the springs will exhibit more of an increase in tension when pressed, than on a long lever.

For any given material, the spring coefficient for a given size wire is more or less independent of hardness. Raising the tensile strength ( and usually the hardness ) by cold drawing, hammering etc, changes the yield point where the wire stays bent rather than returning. The force required to cause a specific deflection is pretty much the same up to the yield point, where hardened wire continues to require more force to increase the deflection, but softer wire just starts to bend. Past a certain point, brittleness develops and the wire will snap rather than ever bend. Spring temper is that happy medium between strength and brittleness.

Brass and phosphor bronze, resist corrosion better than carbon steel like chrome steel music wire, but for the same diameter wire, produce a weaker spring. 302 stainless steel spring wire is similar to the chrome steel, but doesn't work harden as quickly. It doesn't have as high a tensile strength though, so it tolerates less deflection before bending. Spring wire diameter, coil size and number all need to match the material used to get the correct end result. A small increase in coil size can drastically increase the lifespan of a spring.

Dana

[BW77]

Keep in mind, short levers swing through more angle to lift the pad go the proper height, so the springs will exhibit more of an increase in tension when pressed, than on a long lever....

Spring wire diameter, coil size and number all need to match the material used to get the correct end result. A small increase in coil size can drastically increase the lifespan of a spring.

Dana

Thanks Dana and right....The circular mechanism of ( british style) concertinas is a true nightmare when tryin to get all these factors cooperating perfectly. Much easier with a straight uniform arrangement as with accordions or german style chemnitzers/ bandonions. What you say about length of levers probably is most troublesome on the top row of anglos and top notes of extended englishes but I want to add another challenge and that is the variation of pad holes which may cause trouble when adjusting to an even key pressure. Larger holes will need a greater force on the pad to be kept tight which demands extra care when choosing the spring tension and leverage.With too weak springs the pads may tend to leak on push.Usually not a problem with small instruments but it may be obvious with wide range models.

Coil size..agree....I have a feeling many concertina springs have a smaller coil diameter vs the diam of the thread than what usually is recommendable.

[4to5to6]

I've had coils that are too small work there way underneath the levers and stop the pads from closing.

 

Can anyone summarize what the ideal button pressure is for different types of concertinas and different playing techniques.

 

I've always wanted to have the opportunity to play Simon Thoumire's concertina for example. I love the way he does cuts, strikes and rolls. Does he prefer a light action or heavey? Low buttons? Short or long button travel?

[BW77]

1) I've had coils that are too small work there way underneath the levers and stop the pads from closing.

 

2) Can anyone summarize what the ideal button pressure is for different types of concertinas and different playing techniques.

 

3) I've always wanted to have the opportunity to play Simon Thoumire's concertina for example. I love the way he does cuts, strikes and rolls. Does he prefer a light action or heavey? Low buttons? Short or long button travel?

1) That problem firstly is a result from spring being loose or not perfectly positioned but a wider coil might help too of course

 

2) I'm afraid it is a question that doesn't have a simple answer except that you may find pressures in the range 30-80 gram or so, most frequently probably 50-60 gram but it would be of some interest having it investigated of course. Comparing englishes I believe old style instruments, say 1850-90, usually had lighter key pressure than later ones .Is that so? I wonder why in such case ?.... Maybe the leakage risk I mentioned before became more obvious since the limit for keeping pads tight at energetic playing with a common english often is around 30 gram (when the pad holes have equal diameter which I believe was more common too with older style instruments. If the low range holes are made larger maybe you actually need the 50-60 gram to be on the safe side, unless the key pressure will be generally higher in the low keyboard range than at the top. If some maker is reading this please comment !

 

3) Well , on the individual level you better ask the individual player directly. This is really a personal matter but in principle of course the heavier spring action the faster you may play - conditionally that you are strong enough to manage ! Very light action may be seductive concerning "speed" for the same reason and particularly if you are not so strong. With very high key pressure the button touch itself gets painful but a wide flat button might help. Keep in mind that melodeons with much wider buttons can have a key pressure of 150 gram or more while pianos may be around 70-80 gram.

Getting a good staccatto mostly is a matter of playing technique rather than key pressure but try as high pressure as you can cope with if that is what you aim for...

Button travel may vary between 2-4 mm or so. The lift rather should not reduce the opening area for air passage, otherwise it hardly means much for speed I guess. Short travel means you press the button to the bottom and that is not particularly comfortable unless you get wider buttons