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the dreaded drive screw, a new approach to removal

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  • the dreaded drive screw, a new approach to removal

    I'm working on an old electric motor. No pictures in this post, but there will be plenty later in another. The motor was manufactured in 1947 according to the guy I bought it from. It has the remnants of several heavy sloppy coats of paint on it, plus it has been banged around somewhat. There are two nameplates affixed to the outside of the stator. They are not the cool old cast brass ones. These nameplates are thin aluminum. They were each held on by 4 stout drive screws driven into cast iron. Some of the holes were through holes but a few went into ribs in the stator and these were blind holes. I struggled with these and finally got the nameplates off, not without scarring the corners somewhat.

    The first thing I have to say is that I have often read posts wherein someone blithely says to use a Dremel tool to grind a slot, then use a screwdriver. I tried that. I really did. Got out the hammer-type torque screwdrive and everything. After that experience I say BS. That way doesn't work worth beans.

    The technique I developed to my knowledge is new. It requires that the drive screw not be bottomed out in a blind hole. To put it simply, you carefully grind the head down as far as you can without letting the wheel touch the nameplate. Then you get out a small but tough nail set and put it right in the middle and start carefully hitting it with a hammer. You win when the (very thin, hard and brittle) head breaks free from the shaft of the drive screw and the shaft goes a little farther down the hole. The head of the drive screw, which now looks very much like a tiny washer, will pop free and if you got everything just right you didn't damage the nameplate.

    After I finish rehabiitating the motor, I am not going to use drive screws to reinstall. Rather, I'm going to use something like JB Weld. Will it be tough on the next guy to go into the motor? Not necessarily - lots of times I just mask the nameplates and paint. They won't need to come off again until the layers of paint get deep and funky again. Which will not happen on my watch.

    metalmagpie

  • #2
    I have a drain issue currently- this house has a cast iron pipe leading out with a clean-out cap in the end of the pipe. I think it's 6 inch pipe, so the cap is about 5 inches in diameter. It has a square protrusion on it, and I have the wrench. I cannot budge it. I got out my largest crescent wrench and put it on snugly, then put pressure on with a floor jack. All that's happening is the square protrusion is rounding off- the end cap appears to have been glued in place.

    I'll trade you problems-
    I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

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    • #3
      I have had some luck removing drive screws by using a pair of end nippers ground down so that they sit flat on the surface they are up against. I made these originally to use for removing guitar frets when that was a significant part of my life.. Grab the head of the screw, and twist it out. The ones I recall had a very steep thread - presumably they threaded themselves in when hammered.
      "A machinist's (WHAP!) best friend (WHAP! WHAP!) is his hammer. (WHAP!)" - Fred Tanner, foreman, Lunenburg Foundry and Engineering machine shop, circa 1979

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      • #4
        I have a tool manufactured specifically for that purpose. It's a rectangular block of hardened steel with an angled V groove at one end that works as a wedge to pry the screw out.
        Location: Saskatoon, Saskatchewan, Canada

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        • #5
          Originally posted by Arcane View Post
          I have a tool manufactured specifically for that purpose. It's a rectangular block of hardened steel with an angled V groove at one end that works as a wedge to pry the screw out.
          Picture please?

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          • #6
            Originally posted by metalmagpie View Post

            Picture please?



            A couple of websites showed these to be from $20 to $35 dollars. Pretty expensive but I found mine in the surplus section of Princess Auto (Where else? lol) and they were so cheap (really, really cheap!) I bought a dozen of them. I still have 10; I gave two away to friends who are mechanics. Mine, a T109-42 was made (I believe) by or for Carter Carbureter (that's the name on it, with an "e") and measures 3" x 5/8" x 5/16" and the slope on the bottom goes back at an angle of 25 degrees and the notch is 3/8" deep on the bottom side and 3/4" deep on the top side. The line joining the sharp points at the bottom of the two notches is difficult to measure but seems to be slightly over 40 degrees but not 45 degrees.

            A couple more pics are at https://www.worthpoint.com/worthoped...tor-1798297811
            Last edited by Arcane; 01-22-2021, 02:25 PM.
            Location: Saskatoon, Saskatchewan, Canada

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            • #7
              Originally posted by metalmagpie View Post
              IThe head of the drive screw, which now looks very much like a tiny washer, will pop free and if you got everything just right you didn't damage the nameplate.

              After I finish rehabiitating the motor, I am not going to use drive screws to reinstall. Rather, I'm going to use something like JB Weld. Will it be tough on the next guy to go into the motor? Not necessarily - lots of times I just mask the nameplates and paint. They won't need to come off again until the layers of paint get deep and funky again. Which will not happen on my watch.

              metalmagpie

              metalmagpie
              I like your projects,

              Keep them coming... Thanks. JR

              My old yahoo group. Bridgeport Mill Group

              https://groups.yahoo.com/neo/groups/...port_mill/info

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