Dave Prebble Posted November 26, 2003 Share Posted November 26, 2003 Hi All, The spring pressure or 'touch' of an instrument is very much a personal choice and can vary from very light right through to pressures more at home in the physiotherapy department of the local Orthopedic Hospital! Many concertinas have a marked touch pressure variation between different buttons, some being light and others heavy. The ideal for me is to have a light and consistent touch and even button travel across all buttons and a box properly set up is a joy to play. There are a lot of variables that determine touch pressure including, but by no means limited to, Spring alignment and position on the lever as well as variations, even between different springs of the same batch, due to variation in coil diameter, arm length, spring 'open angle' and the like. Some Makers/Repairers seem to be so much better than others at achieving even and consistent results and I freely admit that, as carefully as I try to gauge and compare pressure when re-springing instruments, variations do creep in that only really become apparent when reassembled and played. I do get there in the end but often only through exercising much patience. Given that this a task I don't carry out every day I am unlikely to improve my skill and judgement very much by task repetition so it follows that I have a need for some kind of simple to make and easy to use comparator / measurement device to accurately assess pressures as the job progresses. If I am to believe the claims of some folk that they set each button to exactly x grams or ounces, it follows that they are using some such device to achieve and measure their results. I can envisage some possible solutions, but being a great believer of not 're-inventing the wheel' I would very much like to hear from anyone who has a favourite 'tried and tested' method of achieving consistent 'touch'. Regards Dave Link to comment Share on other sites More sharing options...
goran rahm Posted November 26, 2003 Share Posted November 26, 2003 I use the simplest possible balance according to attached figure. Spring resistance usually about 50g. I have experimented between 30-100 g using button diameters 4-8mm. The combination is essential for comfort. Depending on the leverage and diam of pads you meet different tolerance for lowest spring resistance until some pad may start leaking on push. It may be attractive having low pressure firstly for 'soft and harmonic' style of performance but hardly for fast, energetic,staccatto...and so on. Goran Rahm Link to comment Share on other sites More sharing options...
Richard Morse Posted November 26, 2003 Share Posted November 26, 2003 You've pretty much covered the methods possible though most of them aren't easy to do with existing instruments. We usually limit ourselves to adjusting the spring tension though sometimes we'll relocate the spring if it is clearly in the wrong spot. We have a lot more flexibility in our new concertinas as we can design the lever arm lengths, fulcrum point locations, spring arm lengths and positions (as well as barrel size, wire thickness, material temper, number of winds, etc.) such that we hardly have to adjust the spring tension at all. We use a simple spring gauge to test the button pressure. Ours looks like a thick pencil with calibration marks running down the barrel and a straight wire coming out one end for pressure and one coming out of the other end in a hook shape for testing tension. You simply push the business end of the thing against the button and the marker on the side tells us how many grams of pressure is being applied. Link to comment Share on other sites More sharing options...
goran rahm Posted November 26, 2003 Share Posted November 26, 2003 Interesting Rich, would you mind saying a little more about - what tolerances (variation width of button resistance )your mechanism allows - if you have tested (or your customers..) what variations are preferred and - if you/they have related that to button shape and diameter like I mentioned - you have some 'favourite' button resistance value ? Since I guess you make mainly(only?) 'standard' size instruments do you use same diam pads all over? If not ...have you tried to even out the relations between button resistance/spring force on pads and air pressure? There is an 'inborn defect' in most traditional concertinas since the larger low range pads usually have a tendency to leak much sooner on push than treble pads due to the even (or almost even) spring force acting on them. In principle we would prefer 'as hard springs as possible' as long as they do not get awkward to touch and like I hinted ..for 'soft' playing 'soft' touch seems attractive. Many players I have met however wrongly imagine that light springs might allow faster playing...Well in one way if you have very weak fingers.... The situation/problem is fairly alike with pianoplaying. Just for curiosity I checked the button resistance on a one row modern Hohner....over 200 gram ! Goran Rahm Link to comment Share on other sites More sharing options...
Richard Morse Posted November 26, 2003 Share Posted November 26, 2003 Interesting Rich, would you mind saying a little more about- what tolerances (variation width of button resistance )your mechanism allows Our scale measures point loads so it doesn't matter now wide the button is. If you have tested (or your customers..) what variations are preferred Yes, we've tested many vintage, modern, and our own instruments. People's preferences seem to range from 1.5 to 3 grams. If you/they have related that to button shape and diameter like I mentioned People have individualistic preferences that are all over the board. you have some 'favourite' button resistance value We set our concertina button force to about 2 grams. Since I guess you make mainly(only?) 'standard' size instruments do you use same diam pads all over? If not ...have you tried to even out the relations between button resistance/spring force on pads and air pressure? There is an 'inborn defect' in most traditional concertinas since the larger low range pads usually have a tendency to leak much sooner on push than treble pads due to the even (or almost even) spring force acting on them. We have gutsier springing on larger pads (like the air button on our anglos) but that isn't typical and isn't comparable to the "musical" or "note" buttons. Generally, we find it better to vary the fulcrum and spring mounting point distances to increase the amount of pad force while keeping the same button force the same. In principle we would prefer 'as hard springs as possible' I have never heard of that priciple. Who is "we" (certainly does not include me!)? Just for curiosity I checked the button resistance on a one row modern Hohner....over 200 gram ! Are you sure that your measuring device is accurate? That would mean that it takes almost 1/2 a pound of force to depress that key! Link to comment Share on other sites More sharing options...
Dave Prebble Posted November 28, 2003 Author Share Posted November 28, 2003 Hi Fellas, Thanks for your replies. I had considered both methods as possibilities before posting but having now read the replies I do feel more inclined more towards Richard’s ‘Spring Pencil’ method. It just seems to me that it would be far easier and more convenient to use. I certainly hadn’t considered making a ‘Double Ended’ using the spring in tension with a hook. This is a great idea and could be easily used to assess the actual down force exerted at the pad. (Richard ? Do you use a separate spring for each function??) Whenever I see American tool catalogues (catalogs I guess to most of you over the pond ;-} ), I tend to go green with envy both at the range of stuff available to you Guys and the low prices! Is there some off the shelf ‘ ready made’ tool over there that would do the job or is it a case of making one up? For my purposes I am not too bothered about having a scale calibrated in grams or ounces. It would be enough for me if it is simple, reasonably accurate and capable of comparing pressures thus ensuring reasonably consistent results across all buttons. I must say some of the figures quoted above surprised me a bit. The 200g for a Hohner single row seemed high. I used to play one of the old single row 4 stop models and well remember the very heavy springing. Not a problem for me on that instrument as it seemed to suit the rhythmical English Dance music I was playing and I am sure that the high spring pressure (along with, of course, the resultant snickety snackety ‘pad slap’ accompanyment ) contributed a lot towards the distinctive sound signature of these instruments. I suspect that one reason for the high spring pressure was that the simple ‘button to pad’ action had a very low mechanical advantage compared say to accordion keys but yet each pad still had to resist bellows pressure from a 4 voice reedbank. A couple of seconds shutting my eyes and pressing down with a fingertip on a set of kitchen scales did much to convince me that Goran’s 200g figure is probably about right. (Most unscientific I know Goran, but this time I speak for you J ) That led me to think about the seemingly very low figure Richard quotes of a couple of grams. My kitchen scales are no good at all for measurements in that lower magnitude and I have not yet got a calibrated ‘pencil spring balance’ to measure it with…….There’s a hole in my bucket dear Liza, dear Liza… Whether or not Richard’s device is calibrated exactly in grams matters not a jot in practice. The point is that he is using it to provide a range of reproducible and consistent button touch results to suit client tastes and needs. I have never played one of Richard’s concertinas so therefore have no ‘feel’ (no pun intended) for just how light his springing is. It would be interesting to test button pressure by placing a succession of small washers or coins on a (range of) single button(s) till the spring force is overcome and then weighing them to give a result. It is at the same time surprising how much force a finger can apply with seemingly very low ‘effort’ and also how easily that same finger can carry out very delicate and accurate tasks. Though I am sure we are all capable of 'coping' with instruments with a wide range of spring pressures, as I said right in the beginning, button ‘touch’ is a very much a matter of individual preference and it is up to each of us to find out what suits them best Link to comment Share on other sites More sharing options...
goran rahm Posted November 28, 2003 Share Posted November 28, 2003 Thanks Rich, Before we continue we ought to sort out the discrepancy of measured figures.Something is wrong somewhere.....I refer to 'button resistance' in the meaning what force the button can lift (=balance) in total. This is not related to its surface area either. In most traditonal concertinas this is rather close to the force acting to close the pad since the leverage use to be around 1:1. The "spring force" is greater ...2-3 times or so. I comment anyway on some items: QUOTE (goran rahm) Interesting Rich, would you mind saying a little more about - what tolerances (variation width of button resistance )your mechanism allows Rich:Our scale measures point loads so it doesn't matter now wide the button is. Goran:Maybe I expressed myself vaguely. I meant what variation of button resistance could be practicble with your constructions. My Wheatstones use to allow maybe down to about 30gram until leaking becomes disturbing. With large *hook* action levers you sometimes at low resistance may come across 'play' in the 'hook'. I have hardly come across harder springs than making the button resistance larger than 100gram and in that range with 5mm buttons you get sore fingers easily while with 8mm buttons there may be no problem at all. QUOTE If you have tested (or your customers..) what variations are preferred Rich:Yes, we've tested many vintage, modern, and our own instruments. People's preferences seem to range from 1.5 to 3 grams. Goran: Can you 'translate' that into 'button resistance' ? ? What measure is this 1,5 - 3 grams? I don't quite understand... QUOTE If you/they have related that to button shape and diameter like I mentioned Rich:People have individualistic preferences that are all over the board. Goran: Meaning you have not tried to find out tolerance/preferrence regarding this? Have you not experimented with different diameter buttons at all? QUOTE you have some 'favourite' button resistance value Rich:We set our concertina button force to about 2 grams. Goran: Again:what is measured to this figure? Rich: Generally, we find it better to vary the fulcrum and spring mounting point distances to increase the amount of pad force while keeping the same button force the same. Goran:I haven't seen your instruments....do you use the same type of springs as the Lachenal/Wheatstone concept located more distantly or a completely different type of springs? QUOTE In principle we would prefer 'as hard springs as possible' Rich:I have never heard of that priciple. Who is "we" (certainly does not include me!)? Goran:Well...to clarify....1) we want the pads to be "as tight as possible"...meaning using hard spring force. Of course not in absurdum...(i.e a lot of excess).. 2) for playing efficiency we want the button/pad movement to be as fast as possible...also demanding hard spring force Playing 'comfort' and individual style (playing only 'softly/smoothly' and not staccatto and not 'very' fast) may make lighter 'springing' acceptable/preferrable QUOTE Just for curiosity I checked the button resistance on a one row modern Hohner....over 200 gram ! Rich:Are you sure that your measuring device is accurate? That would mean that it takes almost 1/2 a pound of force to depress that key! Goran:We eveidently speak of different things as said before. The 'button resistance' like I mentioned is over 200 gram. Goran Rahm Link to comment Share on other sites More sharing options...
goran rahm Posted November 28, 2003 Share Posted November 28, 2003 Dave:For my purposes I am not too bothered about having a scale calibrated in grams or ounces. It would be enough for me if it is simple, reasonably accurate and capable of comparing pressures thus ensuring reasonably consistent results across all buttons. Goran:I am waiting for the reply from Rich to clear out the precision of measuring and tolerance of variation before judging the effects. His gauge seem to be a practical method if I understand it right...but if you want really even 'action' I definitely wish to *measure* it...not least in order to make it possible to reproduce the results. Why I use the balance is because it is a lot more accurate than a spring gauge and you get precise results from adjusting steps. The tolerance I use to accept is +/- 5 gram with mean resistance 50 gram. (I like to mention another item if you are going to make a 'perfected' instrument. In many used instruments the button travel distance and button height may vary a lot and for some strange reason many concertina players seem to ignore these for precision of performance elementary facts. Similar inaccuracy would drive any even elementary piano player absolutely mad.....!) Goran Rahm Link to comment Share on other sites More sharing options...
Robin Madge Posted November 28, 2003 Share Posted November 28, 2003 Speaking as an Anglo player, the reason why I'm not too bothered about buttons having a consistant height or travel is that each finger only has to deal with a limited number of buttons and the brain soon compensates. I don't know how many different fingers will be used for each key on a piano keyboard but on the anglo the usual maximum is two. When I was first learning most of my playing was on a single row and only the little fingers had to cope with two buttons, reducing the tactile confusion further. Robin Link to comment Share on other sites More sharing options...
Dave Prebble Posted November 28, 2003 Author Share Posted November 28, 2003 Hi Goran, <Goran...but if you want really even 'action' I definitely wish to *measure* it...not least in order to make it possible to reproduce the results.> Reply: I too wish to measure it accurately but only need arbitrary units for comparison purposes thus I only require a simple divided scale. For my practical purpose there is no particular advantage in making a scale calibrated in grams or ounces. I fully agree with your comments regarding even button travel and button height. You are quite right regarding the ‘touch’ demands of piano players. I also restore and rebuild pianos and confirm that when setting up a key bed, the key height, level and travel are adjusted in increments of a few thousandths of an inch using paper shim washers. Similarly, the touch weight is also adjusted very accurately. Quite often, the only thing required to turn a seemingly mediocre piano into an excellent instrument is the application of proper care and attention in accurately regulating the action. It is a pity that the same attention to detail is not always exercised by some of those setting up concertinas. Regards Dave Link to comment Share on other sites More sharing options...
goran rahm Posted November 28, 2003 Share Posted November 28, 2003 Speaking as an Anglo player, the reason why I'm not too bothered about buttons having a consistant height or travel is that each finger only has to deal with a limited number of buttons and the brain soon compensates. Robin Goran:I agree of course...it is usually much less important with the Anglo than with the English or Duets....But it certainly depends a lot on playing style/idiom too.If you really think of it you will probably find the same as I....often there are great differences ....and if you do compare with a 'perfected' instrument I bet the preferrence is clear....particularly if 'even button resistance' is included not to speak of elimination of friction and precise travel of the buttons..... 'Bushing' as such in my view is a bit overestimated. It certainly may reduce noise but apart from that if the tolerances are perfect you may get more precise conditions without bushings. One alternative solution would be replacable plates with guiding holes with high precision. Once the bushings are worn and buttons get unstable this is a real nuisance but rebushing just takes an hour or two so it is well worth the job. Goran Rahm Link to comment Share on other sites More sharing options...
Richard Morse Posted November 28, 2003 Share Posted November 28, 2003 I refer to 'button resistance' in the meaning what force the button can lift (=balance) in total. This is not related to its surface area either. In most traditonal concertinas this is rather close to the force acting to close the pad since the leverage use to be around 1:1. Actually, the ratio is much closer to 3:5. At such, a 2 gram button force results in a 1.2 gram pad force. I meant what variation of button resistance could be practicble with your constructions. I have hardly come across harder springs than making the button resistance larger than 100gram and in that range with 5mm buttons you get sore fingers easily while with 8mm buttons there may be no problem at all. I still don't understand your question. Our buttons "can lift" from zero to maybe a couple of pounds before the lever arms bend enough to become inoperable. Your observations of spring force and button pressure don't seem to have anything to do with the previous sentence. Goran: Can you 'translate' that into 'button resistance' ? ? What measure is this 1,5 - 3 grams? I don't quite understand... The 1.5 - 3 gram amount IS "button resistance" which you've defined as "force". If you mean "pressure" (force per unit area) you need to ask me for pressure. If you/they have related that to button shape and diameterPeople have individualistic preferences that are all over the board. Meaning you have not tried to find out tolerance/preferrence regarding this? Have you not experimented with different diameter buttons at all? I should have been a little clearer there with my response: We have canvased many people about button force, pressure, button shape and diameter to find that "People have individualistic preferences that are all over the board." And yes, we have experimented with different diameter buttons. you have some 'favourite' button resistance value We set our concertina button force to about 2 grams.Again:what is measured to this figure? Again: Force. "Button resistance" = force. You defined that yourself. If you mean pressure, you must ask for pressure. I haven't seen your instruments....do you use the same type of springs as the Lachenal/Wheatstone concept located more distantly or a completely different type of springs? We use springs similar to Lachenal/Wheatstone. I can't answer your "more distantly" concept because it requires a "than" value. In principle we would prefer 'as hard springs as possible' I have never heard of that priciple. Who is "we"?1) we want the pads to be "as tight as possible"...meaning using hard spring force. 2) for playing efficiency we want the button/pad movement to be as fast as possible...also demanding hard spring force Again: who is "we" Kimosabe? 1) I would prefer the pads to seal with as LITTLE force as necessary. Exessive force would require heavier/stronger components and would degrade parts (excessive friction, pad deformation). Hard (which I assume you mean "strong") spring force is relative to the positions of the spring, pivot fulcrum, and pad. An incredibly weak spring can apply incredibly strong forces upon the pad depending on the leverage it has. 2) Playing efficiency and fastness may have little or nothing to do with spring force. You need to be more specific about your definitions and parameters for meaningful responses. Link to comment Share on other sites More sharing options...
d.elliott Posted November 28, 2003 Share Posted November 28, 2003 Interesting debate chaps, one can tell that the South Yorkshire contingent has been reinforced! We are concentrating on key spring loadings, and the comment has been made that the ratio of pad the key leverage is around 1:1, or was it 3:5. This made me think (ooch). Big reed have big pads, force is equal pressure x area, so springs have to be heavier on big reed keys to avoid pad blow off. So button load increases? But then we often have extremly long levers on big instruments, that require double springing anyway. The bellows have a much larger cross-sectional area thus delivering more air per mm of travel, probably at a lower pressure. So how does all this add together? is there not a compromise between key loading and air tightness, and reed /pad size for a particular bellows configuration? Does anyone have any view of mean pressure deltas accross reeds, and the variences in such deltas between big reeds and small reeds, say G lower baritone, and G above treble cleff? Surely much of the original setting up must have been empirical at best and by serendipity being more likely. I wonder if we are trying to be too scientific. I do believe that the objectives have to be: a good and sufficient pad seal; a posative key load for the purposes of feel, and above all, consistency of resistance. Dave 1 Link to comment Share on other sites More sharing options...
goran rahm Posted November 29, 2003 Share Posted November 29, 2003 QUOTE (goran rahm) I refer to 'button resistance' in the meaning what force the button can lift (=balance) in total. This is not related to its surface area either. In most traditonal concertinas this is rather close to the force acting to close the pad since the leverage use to be around 1:1. Rich:Actually, the ratio is much closer to 3:5. At such, a 2 gram button force results in a 1.2 gram pad force. Goran:3:5...ok that is fairly common..and so is "around 1:1"...I said the later just as an illustration. The big problem remains to clear out the misunderstanding first of all. The 'balancing force' to depress a button (=what I have called 'button resistance) with all British style concertinas I know use to be 30-100 gram. You are speaking of something else Rich due to your figure "2 gram button force" and I have not figured out what it is. "1.2 gram pad force" can not withstand the usual airpressure acting on the pad so there is a rat hidden here.... Can you Dave and Dave find out what it is I have not understood if it is a linguistic problem??? QUOTE (Goran before) I meant what variation of button resistance could be practicble with your constructions. I have hardly come across harder springs than making the button resistance larger than 100gram and in that range with 5mm buttons you get sore fingers easily while with 8mm buttons there may be no problem at all. Rich:I still don't understand your question. Our buttons "can lift" from zero to maybe a couple of pounds before the lever arms bend enough to become inoperable. Your observations of spring force and button pressure don't seem to have anything to do with the previous sentence. Goran: One crucial factor is the force needed to keep the pad tight which is related to pad size, leverage, spring force, button diameter(subjectively) QUOTE Goran: Can you 'translate' that into 'button resistance' ? ? What measure is this 1,5 - 3 grams? I don't quite understand... Rich:The 1.5 - 3 gram amount IS "button resistance" which you've defined as "force". If you mean "pressure" (force per unit area) you need to ask me for pressure. Goran: Again, it does not fit...we are talking about different things....1.5-3 gram is too little unless some very different construction is involved QUOTE (Goran) If you/they have related that to button shape and diameter QUOTE (Rich) People have individualistic preferences that are all over the board. Rich:I should have been a little clearer there with my response: We have canvased many people about button force, pressure, button shape and diameter to find that "People have individualistic preferences that are all over the board." And yes, we have experimented with different diameter buttons. Goran: What I am fishing for is the preferrence among players if having a free choice. The question is interesting from the viewpoint that 5mm concertina buttons from a general 'ergonomic' viewpoint is somewhat absurd. The particular 'musical' demands may ask for something else but this also is a 'traditional' matter in large extent..... QUOTE (Goran) you have some 'favourite' button resistance value QUOTE (Rich) We set our concertina button force to about 2 grams. Goran:And I set mine to 50 grams....:-) I am getting more and more curious about this....I'm not saying you are nuts ..I could likely be....but WHAT is the clue?? QUOTE I haven't seen your instruments....do you use the same type of springs as the Lachenal/Wheatstone concept located more distantly or a completely different type of springs? Rich:We use springs similar to Lachenal/Wheatstone. I can't answer your "more distantly" concept because it requires a "than" value. Goran:Hmm, makes it difficult for me to see how you can adjust 'pad force' for corrresponding to larger pad area by moving the fulcrum much more distantly.It ought to require too much button travel..... QUOTE (Goran) 1) we want the pads to be "as tight as possible"...meaning using hard spring force. 2) for playing efficiency we want the button/pad movement to be as fast as possible...also demanding hard spring force Rich:Again: who is "we" Kimosabe? 1) I would prefer the pads to seal with as LITTLE force as necessary. Exessive force would require heavier/stronger components and would degrade parts (excessive friction, pad deformation). Hard (which I assume you mean "strong") spring force is relative to the positions of the spring, pivot fulcrum, and pad. An incredibly weak spring can apply incredibly strong forces upon the pad depending on the leverage it has. Goran: True of course but the admitted variation is not so wide with the traditional construction. The "Süttner" method ( spring mounted above and distant from the pad acting directly by pressing it down makes this easier. Rich:2) Playing efficiency and fastness may have little or nothing to do with spring force. You need to be more specific about your definitions and parameters for meaningful responses. Goran:With the traditional construction they definitely have since the spring force is decisive for return speed of the pad and button. Link to comment Share on other sites More sharing options...
goran rahm Posted November 29, 2003 Share Posted November 29, 2003 Dave:Big reed have big pads, force is equal pressure x area, so springs have to be heavier on big reed keys to avoid pad blow off. So button load increases? But then we often have extremly long levers on big instruments, that require double springing anyway. Goran: Well it differs...most instruments have the same springs all over and consequently big reed pads DO "blow off" more easily. *Sometimes* there have been effort to compensate with stronger springs. The 'problem in my experience is most evident with baritones (when having even springs all over) Dave:The bellows have a much larger cross-sectional area thus delivering more air per mm of travel, probably at a lower pressure. So how does all this add together?' Goran:Fortunately you 'mostly' don't play larger instruments as forcibly (meaning at high air pressure) not least since the *muscular* force needed to create the equal air pressure makes comfort control yourself.... Compare playing your miniature Dave...you can get almost a painful amplitude with little effort..... Dave:is there not a compromise between key loading and air tightness, and reed /pad size for a particular bellows configuration? Goran: Partly automatic due to the above (last paragraph) Dave:Does anyone have any view of mean pressure deltas accross reeds, and the variences in such deltas between big reeds and small reeds, say G lower baritone, and G above treble cleff? Surely much of the original setting up must have been empirical at best and by serendipity being more likely. I wonder if we are trying to be too scientific. Goran: I did calculate on it some years ago...I agree, that ispartly over-"scientific" since practical conditions limit the possibilities anyway. BUT...this is some of my argument with Rich in the end...maybe one could find a better optimum than the traditional construction admits Dave:I do believe that the objectives have to be: a good and sufficient pad seal; a posative key load for the purposes of feel, and above all, consistency of resistance Goran: Agree, and in my view we face the same wiht all keyboards, not least the computer / typewriter. There is much speaking for that some 'spring resistance' is favourable not only for control but also for comfort and prevention of overuse disorders. "Touch control buttons" may sometimes be seductively 'easy' in this respect. Piano is an interesting object for comparison in this respect and specific instrument model ,individual 'strength', playing style and so on ought to motivate access to wide variations... Goran Rahm Link to comment Share on other sites More sharing options...
d.elliott Posted November 29, 2003 Share Posted November 29, 2003 Thanks Goran for your comments, I often think that we spend a lot of time second guessing the mathematical logic for what was the result of empirical development and practical evolution. This should not prevent us, however, from using more modern approaches to repairing, building and evolving the instrument today. Rich, Goran, Dave! I am wondering if there is a clash of terminology somewhere, your loadings seem to vary by a factor of 100x Can you agree that the load you are discussing is: the static load applied axially to the key that is required to hold the key part depressed and with the pad just off its seating? If all parties report in 'YES' then at least we are comparing apples with apples Dave Link to comment Share on other sites More sharing options...
Richard Morse Posted November 29, 2003 Share Posted November 29, 2003 I am wondering if there is a clash of terminology somewhere, your loadings seem to vary by a factor of 100x There certainly is the possibility that our force tester is not calibrated correctly or that the units have a decimal that doesn't show up. I'm planning on checking it out next time I'm at our shop against a digital scale we have. Can you agree that the load you are discussing is: the static load applied axially to the key that is required to hold the key part depressed and with the pad just off its seating? I agree! I also would like to note that the definition of "load" = overall force. Link to comment Share on other sites More sharing options...
JimLucas Posted November 29, 2003 Share Posted November 29, 2003 If all parties report in 'YES' then at least we are comparing apples with apples Yes, but are they Red Delicious or Granny Smith? Link to comment Share on other sites More sharing options...
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