d.elliott

Over the years this forum has picked over various aspects of concertina design, Some times we attempt to deduce the why's and wherefor's using massive great intuitive leaps, we all do it. Other times we indulge in a more semi-formal process of what is known as REVERSE ENGINEERING This reverse engineering is taking a product, measuring and analysing to re-create the design assumptions, materials to that the product can be re-manufactured or developed, typically a technical process used in the maintenance and re-furbishment of vintage or just obsolete, but still in use, equipment. I think any designer will agree that every design is the product of a series of compromises, strength versus weight, material capabilities, power versus speed, size versus portability, asthetics, maintainability etc etc. These issues were just as valid 1n 1850 as they will be in 2050! The difference is we can deploy a greater degree of knowlege and a far higher analitical capability. I think we often assume that our forefathers had the same advantages as we have today, they did not. I am sure that the highly intelligent Victorian Engineers that created the concertina 'standard', as we know it today, got there through empirical means, trial and error, perspiration and hard work. This is a matter of archeology and second guessing. There are people around like Geoff Crabb who saw the end of this product development process and interacted with people who lived within the process, they may be the only people able to comment with authority. I feel we spend too much time arguing over design assumptions and inadequacies If people want to design a new instument based upon the concertina then let them get on with it, but remember that when some one innovated and decided that a bicycle needed three wheels, it became a tricycle. Dave

Apparently there are two forms of action for the Jackie, one which is riveted which I have not yet seen, and now a riveted type. I examined the non-riveted action, a series of cut out and bent aluminium plates forming a compact lever set. On the one I examined the 'A' button caused the F# to move as well. I felt that the problem may be a design issue, but could be alleviated by dressing the levers with a needle file. Clearly the same problem as you experienced. If you instrument is 'new' or recently purchased from a trade or dealer source, I would NOT open it up as it is likely to be under warrenty, it is best to get the seller to have it repaired or adjusted. As to the Jackie, how is the tuning on the instrument? Have you checked that the notes sound reasonably in tune? Try holding each button down in turn, and with the button depressed reverse the bellows a couple of times, for an English system (and Duet for that matter) there should be no discernable difference in note sound in either direction. Dave

Wow, Paul I have not taken this instrument apart, It was brought to show me by some people for whom I had done some work, on another instrument. I took the opportunity to handle the concertina, nip off and grab a meter, Seiko ST-1100, (around £100 in the UK, probably 2/3 of that in the US so not a cheapo). Our wives were chatting, and we were half joining in, so there was distraction and background noise. I will see these people again in the Spring, and will try to conduct a more measured study. I checked duplicate notes, saw some but little differences, and simply though of age, and that the tuning was fairly consistent say between the 'G's or the 'C's. I shall know what to look for next time and record precise values in all cases. The instument is in very fine fettle, and I do not suspect any form of abuse, but as to reed condition, you never know until you look! Thanks for the interest, I clearly am not up on the mathematics and the implications of my readings, or their degree of imprecision as first reported. Home work required! Dave

Paul looking at your scale, Where is Ab? compared to G# Dave

Sorry Paul, In the distraction, I forgot to note the 'A' pitch varience, I think it was around 15 cents sharp (ish). Dave

I only had around 1/2 hr to make the observations, also with people talking in the bacj ground, the 20 cents above and below zero for the enharmonics was uncannily precise, although there was some small drift between notes on opposite bellows directions I think the figure stands. The 'A', 'D', and 'E' all registered as close to zero as made little difference, the 'F's were actually all closer to +12, and the 'G's closer to +8; but the conditions for measuremnet were not ideal so I rounded them a little. I have looked at your scale, and I need to work it out, I am not up on things like 1/4 comma meantone, I have never heard of this before. I have handled concertinas with unequal tempered tuning before, but this was my first attempt to record some data, I expected the difference, but not the degree, in the enharmonics, but not in the note fequencies Dave

This is by way of sharing information: Wheatstone serial 6725 came a visiting today, it is in amazing coindition, and in its original pitch and tuning. I calibrated my meter to the 'A's of the instrument, so all the 'A's were within 2 or three cents of 0 in both directions of play. As were 'E's, and 'D's. Now the G's all read about +10 cents, as did 'F's and 'C's. Whilst the 'B's read -10 cents, consistently! So far so good, Now enharmonics: in all cases the 'lower' note accidental was 20 cents flatter than I would have expected an equal temprement to be, and the 'upper' note 20 cents sharper. I.E. G# is 20 cents flatter than equal temprement, and Ab 20 cents sharper. D# is 20 cents flatter than equal temprement, and Eb 20 cents sharper Interestingly C# was also 20 cents flatter than I would have expected. this instrument sounds sweet, is chords are beautiful, and all these comments apply and are consistent through out 6725's octaves. There was no real difference on most notes (+/- say 2 cents) between the bellows in or out directions. Unfortunately 6725's owner is bigger than I am, so it went away again. Dave

I usually repair thumb and finger slide attachment (small) screw problems by plugging and using the same or equivalent wood screws. In sever cases I have actualy cut out and fitted new wood tapered inlays, Tapered from the underside so that the scews are not biting onto an end grain. However over the years I have had three or four instances of where the problem had been overcome by using countersunk headed BA, I guess around 8BA setscrews with nuts on the inside of the fretting. Given the tendency to overtighten them, one person had 'double nutted' or lock nutted the screws at the best tension, another had resorted to something like a Loctite 'Nut-lok' fluid to stop the nut un-winding. I also saw that the nuts cut into the much softer wood, and as the inner contour of the wood is not parallel to the thumbstrap plate the bolts are usually twisted over. Eventually this will create a bigger problem. One final problem that I have noticed. The nuts, unless poitioned with a 'flat' tangential to the adjacent pillar had a tendency to provent re-assembly by fouling the pillar. One pillar had been whittled to make clearance. So chaps, fine idea, and definitely the way to go when designing a new instrument, but don't jump at this idea as an instant remedy or super enhancement, it might be more trouble than its worth. Bye the Bye, I have a Wheatsone made Edeophone, (Amboyna burr ended 63key!!!, oops, sorry drooling again) which is about to be returned to its illustious owner. This actually has setcrews/ nuts under the thumbstraps, both thumbstraps had worked loose and these nuts had been Nut-lok retained. Dave

Well chaps, a very nice series of explanations, in lay terms, of quite complex phenomina. The heat treatment, inclusive of tempering adjusts what is known as the 'condition' of the steel. In the British Standards (I am thinking of the BS970 range of engineering steels) the various conditions are specified and are denoted by a letter code, 'T' condition or 'W' condition, followed by a table of mechanical properties. I am tempted to get some reed steels hardness checked, note the tempering colour and look at the implications against say various high carbon spring steels. Not that I can identify particular compositions this way, but I might be able to spot some modern alternatives, and the hardness data might be useful. Dave

Paul/ Clive, on the subject of pipe dreams, I have often wondered about the use of titanium for reed shoes, expensive but.......... Oh, and nickel-silver strip is still available, but the availablility of off-cuts ??? Dave

Rich, Yes Load = overall 'force', in my terms the 'physical weight', in grammes, ounces, milligrammes, pennyweights or any other unit you care to mention. We don't need the complication of 'g' multiplication factors! Calibration would be useful, your device might not be linear, and the scale might be only indicative. Actually I suspect there a decimal place out in a conversion factor somewhere. Goran, your English never ceases to astound me, again I take you back to the word 'Load' a mass, or lump applied to or rested on something. Eliminating the further complication of pressure and contact area on the key top. And Gentlemen all, we are all looking at a position of static equilibrium where the pad is just lifted? Finally Jim, with all these liguistic conumdra, as long as the apples are not French Golden Delicious, who cares? Tin Hat is now on Dave

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

As a school boy, suffering the basics of rudimentary German Language, I was told that you know you have achieved the first level of proficiency when you find yourself dreaming in the language you are learning, even if its all nonsense. Take heart! You are either gaining proficiency in the tune, or the instument, perhaps even both Dave

If by 'play' you mean your cleric to be theatrical, he, she, or it may be thought to be single-acting? with one instument and double acting as an 'Anglocon'. D

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

I never noticed the concavity of the frame sides, but then I did not know to look, I know that I will have another instrument to attack soon, and will check this out. Thanks for the tip Dave

Having worked on and played both brass & Al framed reeds. My observations are: aluminium has the edge in terms of playability, weight {as Dave says}. I have never seen any overt issue relating to Al oxide or corrosion. However brass is easier to work on, tuning etc. it is less likely to be damaged by shims or have tongue inadvertantly shifted. Dave

Hi Dave, Glad you are back! Its good to have your experienced Engineer's input. What about the brass/ bronze spring material used for making the arms on electrical contactors? or is it all solid state these days? Dave

The issue initially raised here is one of treating squeaky bellows, this can only occur where there is abraisive contact /movement. Yes I have noted that there is usually an indication where and when this takes place, and as a professional and practical engineer with thirty years experience I have developed a small understanding of the technical vocabulary. Sometimes its even useful! but it can get in the way, perhaps I should have described the marking as pale rubbing marks rather than witnes marks. As to the 'polish' debate, I have seen and experimented with various treatments, as well as listening to those I know and respect within their craft. I have tried the old fasioned shoe polish, cake in a tin applied by a stiffish brush, and seen the brushing lift the edges of glued joints; applied by cloth it just needs a lot of rubbing in and again mechanial damage may result. Concern was expressed about liquid waxes and oils, remembering that the glues used were animal glues and starch based pastes my concern has been to avoid anything that might cause adhesive failures. Hence my compromise with Meltonian shoe cream, used sparingly to both clean and lubricate the leather. Even though the bellows may have been laquered they will still need cleaning and may need liubrication. I would also avoid the paint it on plastic or silicone based polishes that seem to haunt the shelves of the supermarkets Dave

the 'sound posts' are actually spacers, often with card packers to set the distance between the action box cover and the pad board/ action plate assembly. Their purpose, in conjunction with the special long screws, (particularly on English system machines) is to the transmit the bellows operation and support loads from the thumb straps and finger slides through the delicate fretted cover into the guts of the instrument, without applying undue forces into the action box cover. As Jim said, they all have at least two such spacers or pillars. Their other purpose is simply to hold the cover a set distance from the action board so that it does not collapse inwards. I would judge that any accoustic value would be less than minimal Dave

This problem is also common on older bellows, where the corner gussets fold into themselves. you can often see bright or lighter coloured witness marks were the rubbing takes place. I use shoe cream as an easy to apply (soft cloth), easy to buff off medium, appliable without much rubbing or risk of lifting glued edges. There are also a wide range of colours: Forrest green for green bellows, neutral for around bellows papers, light tan , black etc. In the UK Meltonian is a good brand. Dave

Top half, Bottom half, Left or Right? Sounds messy to live with - no offense intended. Dave

my choice would be an electronic instrument, one that adapted to whichever CD player, gehtto blaster or whatever the kids were using and AUTOMATICALLY TURNED IT OFF. I could then hear my instruments and decide which two others I might just wish to upgrade! Actually I am quite happy with what I have got, but an English System piccolo range would be nice. Dave

Try Neil Gow's 'Lament on the death of his brother Donald', I found this tune two or three weeks before of the sudden death of my closest and dearest friend, played it in a club the night before his funeral. Not wishing to be morbid, but I had found it particularly haunting even before Roy died, more so than Gow's 'Lament for his Second Wife'. Music and emotion, I don't play the tune much any more, but I would recommend it for those more introspective moments. Interesting though, brothers have names, wives have numbers....... OooCh Dave

Ok Team! How many people make, or know how to make pads?? what grade of 'card'? what grade, and nature, thickness of felt? What grade and variety, thickness of leather? what form of adhesive, or contact medium? technique??? Or is it one of life' big trade secret(s)...? PLEASE Dave