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mnl

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  1. I have the Hegner. I consider it without peer. It is dead quiet and very smooth. It takes either scroll saw or jewelers saw blades.
  2. The easiest blanks to source are M2 which is considered to be an oil hardening steel, although for such a small section it will cool before it can make it from the flame to the oil. Daniels shows a pointed form for nonferrous and and rounded form for hardened steel. Drawing the temper will also be interesting. I plan on using my pillar drill as it is easy to get 300-500 rpm that he recommends for brass. It also has a very sensitive feed. It has a Albrecht chuck that holds down to zero.
  3. That is what is referred to as “dubbing” a drill. Almost mandatory for larger drills in brass, especially if you like to avoid excitement. It is probably not feasible in 0.040” and below even if you’d have fine enough abrasives. This discussion has prompted me to pull out my copy of George Daniels book Watchmaking and review his comments on making small drills. I will have to pick up some small drill blanks the next time I order from McMaster and give them a try.
  4. The carbide drills are much harder than HSS so they won’t have as much trouble with work hardened material. Carbide is also much more brittle than HSS so if your setup is not completely rigid the drills will snap as you observed. The work requires a rigid machine, a secure piece, and some sort of center pricked and aligned so the drill stays straight.
  5. The answer is somewhat both, you need a quality drill, but then you also need the proper technique. Prolonged drilling is not a good thing, it means that you are rubbing, not drilling, and the tool is work hardening the material you are trying to drill. There is also a chip load, how much the drill cuts every revolution, but we will leave that for now. Every metal has a recommended cutting speed. For brass it is between 150 and 300 surface feet per minute (sfm). Take for example your #60 drill. It is 0.040” diameter or 0.125” circumference. To get 150 sfm you need to turn the drill at 14,400rpm. There are a few drill presses that can do this, Electomechano made some very nice ones, and others have as well. But very few people have them, so chances are the drill will be turning much slower than optimal. For this you need what is referred to as a sensitive drilling machine, one where it is easy to feel how the drill is feeding, because it is important it cuts all the time. If it rubs then the piece work hardens and it is all over. Brass is more difficult that steel in some ways, because the flutes of the drill try and dig in which can snap the drill. One larger drills it is typical to dub the flutes to reduce or eliminate the rake. It will stop the drill from digging in. That is easy to do on a larger drill, very difficult on a #80. You also need a pretty good drill press to do this. A quality chuck is essential to hold a small drill exactly on center and not wobble.
  6. Stay Brite is 94% tin 6% silver, electronic SAC solder is 96.5% tin, 3% silver, and 0.5% copper. Stay Brite flows at about 280C, SAC at 240C, and lead/tin at about 210C depending on the alloy. I think the higher the flow temperature the worse the bridging characteristics. SAC also is considered to her more brittle than PbSn in most, but not all applications.
  7. You actually could. A lot of people who build electronics do. Most surface mount devices are now soldered using a paste that contains both solder and flux. This is applies to each pad on the printed wire board and the component set onto it. Then it goes in the reflow oven and it is preheated and then the solder is melted. Since there is only a small amount it stays where it is put down. You can use a toaster over for the preheat and then a hot air rework gun to reflow the solder. It takes a little fiddling to sort out the parameters, but it should work for any small metal bits as well. This would be using SAC solder which is lead free. The reflow guns can be had fairly cheaply on the web.
  8. Lard oil is pressed from lard. It has been the go to cutting fluid for copper for years beyond count. It sets up just below room temp so when the shop is cold in the winter it has to be warmed to liquify it. It will also get rancid, so keep cold when not in use. There are other fluids that work almost as well for copper, just don’t use anything with sulfur in it. It will turn everything black.
  9. Why not use glass for the port lights, or at least try to? Get some microscope cover slips, glue one down to a piece of very smooth ply or wood with some shellac, CA, or whatever you find easy to dissolve away. Chuck up a piece of your brass tube in a slow speed drill press, and using some abrasive paste or Clover compound core your way through the glass. Once through, dissolve the adhesive away and there is your glass disk. I have never done this with a cover slip, but have done it successfully on slightly thicker pieces of glass. It will take a bit of fiddling to get the parameters straight, but it should work.
  10. If it is a modern design the shrouds will be rod, and probably 1/4” or 6mm. Only if it has a really large sail area for its size, think Farr ( old Mumm) 30 might the highest load segment be 8mm. That would probably be V1 for multiple spreaders or D1 if single spreader. You will never see the headstay as it will be covered by either the foil for the jib luff or the roller furler. The backstay can be either rod, wire or both depending on the type of adjuster. All will terminate in some sort of tang to attach to turnbuckles or other adjusters. Running backstays or checkstays could be wire or now more likely pbo or Amsteel synthetic. These will be lighter and lower stretch than wire. When in doubt go for the cleaner, lower windage/drag solution.

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