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Dana Johnson

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About Dana Johnson

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    Heavyweight Boxer

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  • Interests
    Playing ITM and making concertinas
  • Location
    Kensington Maryland. USA

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  1. It is easy to call something by a name that has the connotation of quality. Fully machine made reeds need larger tolerances, since the punching process for both the windows and reed blanks produce very slight size differences that together can cause an interference fit if a tight window matches up with a wide reed. As such, if your punch sizing eliminates this problem, you have reeds that can go from a good fit to a very open fit from the same punch set. Hand finishing allows you to start with tighter fitting blanks and work to a tighter tolerance that can be more uniform from one reed to t
  2. One thing to keep in mind is that woods lose moisture to the air at a much higher rate than they regain it. This is especially true for thin wood like violin plates. In concertinas, the pad boards are generally one of the thinner parts, with the reed pans being next. The ends if wood, are commonly laminated and are less vulnerable. Room or house humidity control avoids the sharp changes of in case to out. In case humidifiers are a second best, but still worthwhile bit of insurance. I have used a large console evaporative humidifier for a long time for my shop to aim for that
  3. Alex West, I used a US. Uddeholm distributor since that is where I live. Since they are a European company, you ought to be able to find a distributor on the company website. I was lucky to be able to buy a minimum order including different thicknesses, but still have a lifetime’s supply I have been sharing with a friend. The Sandvik version sounds a reasonable choice too. I have been using (small ) 18-8 stainless nuts and bolts for the past 25 years dry with zero problems. If you don’t have to tap anything, I’d say stick with the best corrosion resistance alloy. That is the
  4. Don is quite right, though the strap is more to keep the bellows from opening up somewhat on it’s own and needing more pressure on the press notes when nearing more closed than the resting state. A hard case with corner blocks eliminates the need for a strap and provides vastly more protection to your possibly expensive instrument. You aren’t likely to over-stress the bellows taking it out of the bag unless the bag is too small. If you haven’t bought the concertina yet, spring for a hard case with it. If the cost of the case is a good portion of the price, you are likely to want a better i
  5. Chris mentions stainless on stainless as being prone to galling, but as always the alloy counts. 300 series stainless should not be used together with itself or others of the same series. The nickel content is the culprit and on a molecular level will jump from one surface to the other. You can use 300 series in combination with 400 series ( chromium only )without galling. On a different note, I believe some Wheatstones were made with the best quality reeds advertised as having purposely rounded edges. Reed steel should be hard enough already. I find the blue 1095 shim steel
  6. Valves can affect tuning, but that does not sound like this is your problem. Valves can change stiffness over time, Initially stiff valves with the reed tuned under that condition, may become more flexible with use and the reed pitch will rise, sometimes by quite a bit. Likewise a flexible valve may grow stiffer with age “drying out “ and lower the pitch a bit because it won’t lift high enough to allow free air flow. Notes that are played often tend to keep the valves flexible, though aging often causes valves to curl away and need replacing. Reeds can change pitch if they change the
  7. When I make bellows I think carefully about the “grain” direction. In the top and end runs I want the stretch direction to be across the strip, rather than lengthwise. As the leather bends at the peaks I want it to be more flexible. I save most of the backs on my skins for that, while the gussets are better far down the sides and near the belly. Butterflies are not grain critical and easily use up the remaining areas of the skin. For reed valves, the grain should be in the long direction of the valve. This means the valve resists bending more and will tend to snap back to flat, where t
  8. Hi Tom, I mostly always mean the acoustic wave form that is the end result of the vibration of an air driven reed. I am aware of the variations and combination of the bar modes for a reed that is excited by other means but see zero evidence of their frequencies in the resulting sound. If you put a magnetic pickup near a reed and drive the reed sympathetically, ( no air flowing by the reed) the bar modes are all pretty strong, so they should at least appear as visible peaks in the spectrum. Hope you are staying well, Dana
  9. 30 years ago, I measured reed resonances (not harmonics ) produced by sympathetic vibration to the sound a variable audio oscillator produced. All the reeds I tested produced very similar results. I used a little laser bounced off the reed tip onto the wall to find the different peak amplitudes without affecting the reed by proximity to a magnetic field. (Not really important. I did the same thing using a tiny magnetic pickup ). The resulting resonances were not at all linear, though I seem to recall that each successive resonance was roughly about 2.3 times the previous resonance, not the f
  10. Talas sells a glue for bookbinding “Jade R” that is a combination of PVA and another adhesive that I find excellent. I used to use Jade 403 which was good, but not reversible and had a little odor. They added Jade 711 which has almost no odor and works as well. The Jade R is reversible ( that’s what the R is for ) and all of these adhesives are archival and remain flexible. I’m not sure where hide glue for bellows comes from. It certainly was used for the woodwork, as evidenced by old loose corner blocks, but in the Pathe film of the Wheatstone factory, shows a white brushable past
  11. It would be about the most difficult stock to work with even if it was an appropriate alloy. Ordinary 1095 spring temper steel ( 0.95% carbon steel ) is readily available in sheet form which makes perfectly good reeds. The blue temper is a little softer than ideal, but it doesn’t affect the sound, only the resistance to changing its set after initial tuning. Reed steel for accordions etc. is tempered a little harder. I haven’t used it, but supposedly old clock springs are a little harder temper of that alloy, but it might be worth it for making a replacement reed, but not for making whole r
  12. Re: Richard’s reference to my concertinas, my pivots have evolved over the last 25 years, as have my springs, but all had the same aspect of being a downward pulling spring between the pivot and the pad rather than the normal upward spring on the button side. All get tested for about 4 million cycled to check for wear, which even then is negligible. I like the down spring because it keeps the pivot in contact regardless of any button pressing ( referring to Alex’s comment on hook actions ), Is wear compensating compared with rivets which can eventually wear their holes oblong causing clicki
  13. The wheatstone way Steve Dickinson showed be was to peen the rivet over tight, then invert it over a head sized shallow hole in the anvil and give the rivet a tap , causing it to release just enough to leave the lever free. It was quick and easy. Dana
  14. Reeds at their quietest enter the window until they reach a depth where the increased clearance allows enough air to pass by the reed to drop the forces causing the motion. Reed momentum carries it to a point where the return spring force is greater than the remaining air flow forces. Reeds like concertina reeds with a back draft angle in the window allow the reed to dump air on the sides of the reed as well as at the tip and can operate at lower pressure than reeds with vertical window walls, where the increasing gap at the tip is the only avenue for the air to pass by the reed requiring th
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