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  • ed_h's Avatar
    05-14-2017, 11:11 AM
    ed_h replied to a thread LED bulb resistor?? in General
    At zero length, material or temp wouldnt matter. Fabrication issues issues might be tricky, though. Ed
    35 replies | 1748 view(s)
  • ed_h's Avatar
    05-13-2017, 09:22 PM
    ed_h replied to a thread Electrical question in General
    True, but the fact that the OP explicitly called out 240 vac suggested to me that he was in the US or some other place where "normal" mains voltage...
    10 replies | 806 view(s)
  • ed_h's Avatar
    05-13-2017, 10:43 AM
    ed_h replied to a thread Electrical question in General
    Far superior to what you have now. In fact, switching just one side of a 240 v supply is a really bad idea. Ed
    10 replies | 806 view(s)
  • ed_h's Avatar
    05-13-2017, 10:37 AM
    ed_h replied to a thread LED bulb resistor?? in General
    You really need the LED specs to say for sure, but a 1K resistor should give you around 12 mA peak current, which should be fairly safe. You could...
    35 replies | 1748 view(s)
  • ed_h's Avatar
    05-12-2017, 12:59 AM
    I had a '74 Triumph TR6 that sat in my garage for over 30 years. Needless to say, the fuel tank spent most of that time empty. Yet when I removed...
    22 replies | 1473 view(s)
  • ed_h's Avatar
    05-09-2017, 03:22 PM
    The bushing you describe sounds like so-called "Super Oilite". It's a ferrous based, sintered, oil impregnated material. It actually has specs...
    15 replies | 1353 view(s)
  • ed_h's Avatar
    04-25-2017, 11:34 PM
    ed_h replied to a thread OT: Wood board load limit in General
    Yup, overbuilding a little is a good idea if you can. I built the house I live in, and some other assorted smaller structures on the property. ...
    14 replies | 1165 view(s)
  • ed_h's Avatar
    04-25-2017, 09:04 PM
    ed_h replied to a thread OT: Wood board load limit in General
    The 1/3 rule works well for 2 x 4, marginally for 2 x 6, and not very well for larger sizes. The strength of a beam is proportional to the width...
    14 replies | 1165 view(s)
  • ed_h's Avatar
    04-25-2017, 07:03 PM
    Mill scale is a complex of iron oxides not so different from rust. I find that rust removers work similarly for scale. Ed
    30 replies | 2041 view(s)
  • ed_h's Avatar
    04-25-2017, 04:26 PM
    ed_h replied to a thread OT: Wood board load limit in General
    I use this formula for thumbnail calculations: Max Load = (fiber stress x width x depth^2)/(9 x length) width & depth in inches, length in feet...
    14 replies | 1165 view(s)
  • ed_h's Avatar
    04-25-2017, 04:19 PM
    HCl is a gas and hydrochloric or muriatic acids are just HCl dissolved in water. This is what's behind muriatic acid's reputation for being able to...
    30 replies | 2041 view(s)
  • ed_h's Avatar
    04-02-2017, 11:43 AM
    ed_h replied to a thread The only way is up in General
    Good catch, Bob. I should have worded that a little better. Glad she doesn't follow this board. Ed
    21 replies | 2204 view(s)
  • ed_h's Avatar
    04-01-2017, 08:40 PM
    ed_h replied to a thread The only way is up in General
    Ha! Tell me about it! http://bullfire.net/Mill/Milling%20Machine.html I consider a basement shop ideal in many ways. My wife, not so much. ...
    21 replies | 2204 view(s)
  • ed_h's Avatar
    04-01-2017, 11:42 AM
    ed_h replied to a thread OT: Cool Mind Bender Video in General
    I believe thats a 2-D Hilbert curve. It's a 1-D curve that can fill a 2-D plane. I've not seen it generated that way. Thanks. Ed
    2 replies | 369 view(s)
  • ed_h's Avatar
    03-30-2017, 08:52 PM
    ed_h replied to a thread Electrolysis, and cast iron. in General
    My experience with ER would not support the claim of 1/2 pound of rust. It works and works well, but for me it seems to wear out fairly quickly. ...
    71 replies | 5082 view(s)
  • ed_h's Avatar
    03-30-2017, 06:45 PM
    ed_h replied to a thread Electrolysis, and cast iron. in General
    4) ER is also a good approach if you need to preserve zinc or other plating on a part. Most other methods will attack it. 8) I think Molasses may...
    71 replies | 5082 view(s)
  • ed_h's Avatar
    03-30-2017, 04:16 PM
    ed_h replied to a thread Electrolysis, and cast iron. in General
    I wonder if what some think is flash rust after a phosphoric acid treatment is really just some iron phosphate left after drying, which can present...
    71 replies | 5082 view(s)
  • ed_h's Avatar
    03-30-2017, 03:50 PM
    ed_h replied to a thread Lithium battery question in General
    You certainly could be right about what's used in power tools--I haven't taken any apart. I was just pointing out that the general heading "lithium...
    19 replies | 1246 view(s)
  • ed_h's Avatar
    03-30-2017, 12:42 PM
    ed_h replied to a thread Lithium battery question in General
    All lithium cell technologies I'm aware of require charge (and, ideally, discharge) monitoring at the cell level. Given that, lithium iron phosphate...
    19 replies | 1246 view(s)
  • ed_h's Avatar
    03-30-2017, 11:21 AM
    ed_h replied to a thread Electrolysis, and cast iron. in General
    I think this may have been mentioned before, but the black smut is probably one or more of the following: magnetite, a reduced form of iron oxide,...
    71 replies | 5082 view(s)
  • ed_h's Avatar
    03-30-2017, 11:05 AM
    ed_h replied to a thread Lithium battery question in General
    Some variants of lithium cell chemistry are much safer. E.g. lithium iron. A little less energy density, though. Ed
    19 replies | 1246 view(s)
  • ed_h's Avatar
    03-20-2017, 05:59 PM
    Apparently sodium power cables are (or were, at least) a real thing: http://dx.doi.org/10.2172/5949513 Ed
    22 replies | 1744 view(s)
  • ed_h's Avatar
    03-19-2017, 08:35 PM
    ed_h replied to a thread OT CPU at 100%? in General
    Many moons ago when I was an undergraduate EE, we typically had a choice of microprocessors to use for labs and projects. We could buy a Motorola 68...
    44 replies | 2463 view(s)
  • ed_h's Avatar
    03-19-2017, 04:42 PM
    ed_h replied to a thread OT CPU at 100%? in General
    Me three. Had nothing but heartache with Windows update--both the process itself and some of the "updates". Anyone else had trouble with their...
    44 replies | 2463 view(s)
  • ed_h's Avatar
    03-18-2017, 03:37 PM
    ed_h replied to a thread OT CPU at 100%? in General
    I also had the plugin container.exe issue with firefox. This is on Ubuntu. Ed
    44 replies | 2463 view(s)
  • ed_h's Avatar
    03-14-2017, 12:20 AM
    I believe re-seating is the most effective way to fix a contact problem like that. Contact cleaner is more for contacts that open and close, so...
    24 replies | 1467 view(s)
  • ed_h's Avatar
    03-09-2017, 03:02 PM
    ed_h replied to a thread method for making a dome in General
    Bucky was a bit of an odd duck, but he was a media darling, so he got a lot of exposure. I'm not sure if his tensegrity structures would have caught...
    30 replies | 2742 view(s)
  • ed_h's Avatar
    03-09-2017, 12:19 PM
    ed_h replied to a thread method for making a dome in General
    Regular hexagon tiles will only produce a flat surface. Including regular pentagons at specific locations will pucker the surface into a closed...
    30 replies | 2742 view(s)
  • ed_h's Avatar
    03-06-2017, 03:40 PM
    ed_h replied to a thread Rocker Arm Attachment in General
    Yes, I see what you mean. I guess if you were going to sleeve the rocker bores and did that first, at least you'd have consistent bores to work...
    22 replies | 6406 view(s)
  • ed_h's Avatar
    03-05-2017, 12:09 PM
    ed_h replied to a thread Rocker Arm Attachment in General
    Dave-- Could you machine a cylindrical sleeve to locate the rocker instead of the cones? That should reference the ground surface to the bore...
    22 replies | 6406 view(s)
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