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JD Rogers

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  1. Concertina connection https://www.concertinaconnection.com/ uses a thin gauge steel wire as opposed to the thicker phosphor bronze and explains why here: http://www.concertinaconnection.com/about_ airflow.htm I made a spring winding board and could post photos if you want to try it yourself. Similar to Alex Holden's https://www.holdenconcertinas.com/?p=831 but a bit simpler for doing small quantities I needed. I am very happy with the result. As for the physics, my take is that you have 2 parameters you can control: 1. spring constant k, determined by the material (type, temper, thickness), coil diameter, and the number or turns. 2. Where on the displacement curve you start (more pre-compression when the button is up is farther out on the curve) Those two parameters affect the force and the force profile as you push the button, but the effect of profile is pretty small for the range of motion of a button. The main thing is the initial force. Since you can lighten that by setting the spring angle when it is unhooked, you may not notice much difference with different materials. But it will be interesting if you do! Wakker has some good info on his site, including the tip that while it might seem like a good idea to have light springs, this does not necessarily mean faster, because the spring does not snap the pad closed as quickly, and you may end up with insufficient pressure to provide solid seal and prevent leaking air throughout. I feel like others have some good info as well, perhaps Tedrow? Others, please chime in if I am forgetting any! JDR
  2. You also may be able to tidy up the belt leather to be fairly comfortable. Mark's straps are comfy and nice looking (especially with the bells and whistles like gold tooling). But for functionality, you can probably get pretty far by cutting the straps to the shape you are aiming for, slightly oversized, and then sand down any sharp edges to create a bit of a bevel.
  3. I second that. It would be good to have low expectations on delivery time, but he will come through eventually. Sometimes, for various legitimate reasons, I have waited a long time. Once due to customs and recently many months for straps as he had to wait on leather supply (along with the rest of the world supply chain lately). He also responds to email, and it is worth following up via phone or email since you haven't heard from him yet to make sure your order didn't fall through the cracks.
  4. I am a big fan of a well-made, aesthetically pleasing case. My suggestion does not fall into the aesthetically pleasing category, but if you are looking for something for gigging, you might consider pelican or nanuk cases as they are watertight. The advantage is that they also help keep the humidity up if you live in a climate that has to deal with heating in the winter. I know many use the pelican storm im2075 for single concertinas, but the nanuk 918 works well for 2.
  5. This particular flavor has been coming up a lot lately, usually a couple posted at the same time for the same $2.90 or $2.75 and the image that says don't bid, contact us for direct sales. I think this is at least the 4th round in the past few months. Also frequently listed as a "wheatstone lachenal" or "Jeffries Wheatstone" or similar juxtaposition with a modern maker's name.
  6. I can't claim expertise on this topic, but I have spent enough time tweaking reeds on enough instruments that I may be able to add something.. Clarification questions: is this english, anglo, hybrid, etc? Valves: The no valves thing raises a red flag in my mind. If other reeds behaving well at similar pitch are valved, but the opposing reeds on the inefficient buttons are not valved, that could be a factor. My understanding (and would love for others to fill me in if this is an incomplete understanding) is that the highest reeds don't need valves because they are unlikely to start vibrating when air is coming from the wrong direction on the shoe side, and the leakage is small because the reed is small and stiff. So to confirm, are the opposite reeds (push vs pull) unvalved on the inefficient D''' and G''' notes? Valves being cheap, it may be worth trying to valve those to see if it solved the problem before other more dramatic undertakings. Tolerance (another sources of inefficiency): Again, I would love to hear from others, but in my limited experience, reeds that have a larger gap or lower tolerance tend to be inefficient, That makes complete sense to me. As the reed tongue end passes the top of the reed shoe, if there is a gap between the sides or the end that allows air to pass, more air passes without being converted to pressure variations (sound waves). If the reed is perfectly matched to the reed shoe, the reed is more efficient. This sort of 'leaking' could be due to a gap on the sides, or a gap at the end, or a tongue is shaped such that the end and sides pass the top of the reed shoe at different times (think of a curved reed). That might do interesting and possibly good) things to the voice of the reed, but would likely reduce efficiency. There is a downside to high tolerance: The highest tolerance reeds I have encountered are on my wife Kara's Dipper, and they have extremely tight tolerance and are extremely efficient. But this Dipper suffers more with environment changes. Any change in humidity (and we keep all the instruments as close to 50% as we can in the winter using plastic bins) tends to lead to buzzing reeds and other problems. My guess is this is because the slight swelling or shrinking of reed pans changes the pressure on the reed shoe and the tolerance is so tight that even a small change leads to interference on these high tolerance reeds. The last thing I can think of is if there is simply a leak on these reeds because the reed show is now well seated in the reed pan. It may be worth confirming that the reeds are comparably tight in the reed pan compared to the others that seem more efficient. Best, JDR
  7. Hi All, I think this is a fascinating topic. I assumed the levers on Lachenal's were round rod/wire stock bent to form the correct kinked profile and then press or rolled. I imagine this flattening gave better stiffness in the direction of action, but perhaps work hardened the metal some as well? It would be interesting to know what equipment has been preserved by Wheatstone from the Lachenal acquisition. I'd be curious if anyone knows more about the process or the rationale. I know the levers can also be replaced with riveted action constructed de novo, but it is interesting to know how one would at least try to restore to original condition, especially if you plan to keep the levers that still work in place. I have a similar challenge with an old Crabb that has some missing rivited levers. These are round profile, flattened only where the rivet attaches, and I have gone to great pains to acquire brass rod of a similar diameters. I used an arbor press to flatten the section for the rivet, and had to tinker with filing hardened steel to get the correct profile. The posts will not be easy to match, as they appear to be stamped out of thick sheet and filed to a point. I only need a few, so just plan to get as close as I can with filing/grinding down some bits of flat stock. It's all a bit more work than one should spend to get a workable lever, but you do gain some insights into the process used over 100 years ago, which is kind of fun. We all know you can't get modern threads to match the old end bolts, but it seems that the rod diameter used back then was not a gauge that is currently made in any system of units either! (or perhaps the tolerance was just poor and there was lots of variation.) Jeremy
  8. Hello Paul, I am curious what the person you have lined up will be using, i.e. CNC or laser? What file format would they require? I have not done this, but I have pondered it some. I imagine that a good photo (would need to take care to correct for distortion or possibly use a flatbed scanner) could be processed with thresh-holding to get the pattern as a jpg/png/bmp format. It might then be possible to convert this to paths or SVG and eventually to a CAD format required. I would be moderately concerned that depending on the way this is done (image processing and physical cutting tolerances), the fretwork would be thicker or thinner than the original. Though probably better than "missing" or made from blue acrylic. ? I would imagine one could try a few test runs on cheap material and tweak it to get it right. Also, there are a number of different lachenal fret designs. Which do you have? It might be interesting to set up a process or workflow for this. Jeremy
  9. Thank you Geoff! This information is a valuable resource and I'm so glad you decided to make it available. As one in possession of two instruments form the first page, it is fun to have an idea of where they fall in the history of this great family of concertinas. There are some very interesting notes that you have included. Any idea why the numbering started with 8071? I am not at all surprised they start at a high number, but one wonders if it was an arbitrary number, or had some meaning. It is curious that the stamped numbers were not used consistently for resold instruments until 1895. Were early J Crabb instruments with stamped numbers indicative of an instrument that was not originally build for resale? I have one from that late 1880s that is stamped, but also appears to be sold by Ball Beavon. Perhaps it was not commissioned, but resold and stamped externally by Ball Beavon later? It is also really interesting that the total number of instruments produced per year appears to have hovered so consistently right around 20/year from 1876-1907. There are a few dips, but usually followed by a jump the following year, which makes me wonder if the numbers were assigned when the instrument was completed or when it was started. I'm also curious about the 337 number in the final table. The serial numbers progress from 8321 in 1889 to 8503 in 1895, so that sounds like a total of 182 in 7 years or 26 per year. All very interesting. Thanks again for sharing! Best, Jeremy
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