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Saint George

Discussion in 'Amplitude Modulation' started by W7TFO, Mar 9, 2017.

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  1. K4KYV

    K4KYV Premium Subscriber Volunteer Moderator QRZ Page

    Isn't it easier to just use a manual tap handle and turn it by hand? Whenever I'm tapping a hole, I use the tap handle. Once the threads bite, I turn it a fraction of a turn, then back it out and clean out the shavings, thread it back in and turn it some more. Kind of like tuning a piano, turn it a bit, then back it off a little, and periodically removing it completely and cleaning out the shavings. Do this until it's all the way in. Of course I use thread oil for steel and other hard metals. For softer materials like plastics, I have some other stuff that appears to be water-based, that more closely resembles soap and water.

    If I don't periodically clean the tap as I go as described above, eventually a shaving gets stuck in the threads and there goes the tap.

    It takes extreme care when tapping a hole that bottoms out in a thick piece without going all the way through, and you need a second tap to finish the job, one that's almost flat at the end, with only a few threads of taper. I forget what those are called. If you do break the tap, might as well throw that piece piece away and start over.
  2. W7TFO

    W7TFO Platinum Subscriber Platinum Subscriber QRZ Page

    Don, I have almost 800 holes there to chase.

    Come on over with your wrench and dive in!

  3. K4KYV

    K4KYV Premium Subscriber Volunteer Moderator QRZ Page

    From the photo it looked like an ordinary relay rack at first glance, but I see now maybe it's a frame and panel cabinet job. Whoever built that thing used a hell of a lot of screws, if every single hole was filled with a screw. In that case, I'm glad I'm not the one who originally drilled and tapped them. Maybe the original builder purchased the frame members already factory-drilled and tapped. I would have put in a screw about every 6" and left the rest of the holes blank. I thought I was bad about overkill. I'm equally glad I didn't have to drill the matching holes in the sheet metal panels and make them all line up. I hate sheet metal work.
  4. K4KYV

    K4KYV Premium Subscriber Volunteer Moderator QRZ Page

    I save every piece of cloth-covered wire I can find that still has good insulation, even short pieces when I part out an old piece of equipment. Nothing ruins the restoration of a vintage piece more than using modern plastic hook-up wire and the wrong kind of fasteners, unless it's plainly visible orange drops in a piece of 1920s equipment. I save every nut and bolt when taking something apart. Many are sorted in boxes by size. If an ancient piece is missing hardware, I pour my nuts, bolts and screws out, box at a time, into a large Army mess-hall cooking sheet I pulled from a dumpster, sort through and try to find identical replacement hardware, something you will never buy from Ace Hardware or even McMaster-Carr. The wrong kind of fastener sticks out like a sore thumb. I used that construction approach with my HF-300 rig. OTOH, when I throw something together out of what is easily available and mostly just care about making it function, my 8005 rig for example, I don't worry so much about appearance, and may end up with mixed hardware and styles of hookup wire, meters and knobs.
    WA3VJB and N2EY like this.
  5. K5UJ

    K5UJ Ham Member QRZ Page

    I've never had to remove powder coat from rack threads but I wonder if there's another way. You can get powder coat stripper but it's nasty stuff. Nevertheless, if you got a small can, a bunch of Q tips and get the rack outside in the open air, maybe putting some stripper in each hole and leaving for 20 minutes or so, then rinsing with water would help.

    Another possibility is a tiny wire brush and dremel and buzz out each hole with that. A regular rack screw and some oil might work out what's left. I think if I ever get a rack powder coated and it has permanent rails, I'll just mask over them.

    That's a complex structure that appears to be mounted in the rack, the one painted light gray. I can't really tell how it is eventually going to be used. It looks like a rack shelf but custom made for something. Well, I'm not really up to speed on the Saint George thing but I'm guessing it's an old Westinghouse rig.
  6. K4KYV

    K4KYV Premium Subscriber Volunteer Moderator QRZ Page

    Using a tapered tap turned by hand would probably be the easiest way for a normal rack, but 800 holes would be a problem. Another possibility, gather a bunch of short screws and screw them in from the back side. After the powder coating is done, unscrew them with a nubby screwdriver. I assume Dennis has a steady hand and his drill has a SLOW speed setting.
  7. W7TFO

    W7TFO Platinum Subscriber Platinum Subscriber QRZ Page

    I'd've thought it obvious I'm the original builder. The project will use a lot of vintage Westinghouse components, hence the moniker.

    There are two 23" racks, spaced apart, and bolted together fore and aft to form a very strong chassis to hold some very heavy iron.

    Everything is aluminum, and when completed will appear as a closed in cabinet with access from all sides.

    I do all my own metalwork, and yes, I'm very detail oriented.

    The panel mounting screws are all 12-24, slotted round head. Using anything else would be anathema!

    Of course I'll never use every hole, no one does in racks. But they have to look clean & orderly.

  8. K4KYV

    K4KYV Premium Subscriber Volunteer Moderator QRZ Page

    I had the impression that the cabinet was re-purposed from a commercial transmitter. My error. Are those 12-24 round-heads plated or bare steel? If you really want to make it look vintage, they need to be unplated; bright shiny ones stick out like plastic hookup wire and orange drop capacitors. Paint won't readily adhere to plated steel either. I remember re-building a vintage transformer years ago, and one of the long screws that held it together had broken. I couldn't find an unplated replacement screw the right size anywhere on the face of the earth. The whole thing would be re-painted in the end, so I took a butane torch and heated a plated screw red-hot long enough to burn off the bright plating. After it cooled, the dull greyish residue left behind took paint very well.

    This can be taken to neurotic extremes. I recall a Model-T collector and restorer who insisted that every nut and bolt had to be an exact replica of the original, down to the style of bolt-head and some little mark stamped on it. That hardware, either original or replica, was available from some speciality house, each at a highly inflated price. He insisted on purchasing them, even for spots where the bolt-head would never be seen without pulling the engine!

    I'll be looking forward to seeing photos of the rig when it is finished.
  9. W7TFO

    W7TFO Platinum Subscriber Platinum Subscriber QRZ Page

    "I'll be looking forward to seeing photos of the rig when it is finished. "

    This thread will follow it up to birth and after, that is if I live long enuf to enjoy my OCD.

    N6YW likes this.
  10. N2DTS

    N2DTS Ham Member QRZ Page

    Looks like a telco style open frame rack, screws usually push the paint/powder coat out but they also have self taping screws we use to mount equipment.
    I have seen some new racks that were not tapped at all, but think they are aluminum.

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