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  • Screwdriver

    With the introduction of a myriad of different types of screw tips...
    Phillips, Pozidrive, Robertson [sq-drive], clutch, assorted security types, Torx...etc etc etc And their popularity......

    Why do we still have the straight slot screw?

    I can't recall the last time I reached for one. I typically replace anything with a straight slot screw.

    OK, The only straight slot screw in quantity in my home are the ones holding the various cover plates on my outlets and switches.

    Cactus Man

  • #2
    Re: Screwdriver

    I like some of the drives... I particularly like square drive and pozi for use with a power tool. I could do without torx, especially the real shallow ones that need the bit to be held perfectly square or it slips out. Give me a ball hex driver anytime!

    But all the variety makes life a pain when you're working in a restricted space and can't see the head well. You end up with all your bits out, trying to find the one that fits... by braille.

    And I get downright ticked off when all I can find at HD or Lowes in the size I need has a different head type than I'm using on the rest of the project. Aaaargh. As an engineer we try to design so that the absolute minimum different tools are needed to perform service, so it's frustrating on home projects to have to use a couple of torx when the rest of the project all uses square because that's all I could find without running all over town.

    I commonly use straight blades for repairs. When a screw head breaks off (&*%^* Chinese hardware!!), grab the dremel with cutoff wheel, cut a screwdriver slot in the shank. Works a lot of the time and it's way faster than an ez-out.

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    • #3
      Re: Screwdriver

      Interesting - I usually go the other way, and replace slotted with Pozidriv if I can, or plain old Philips if I can't (ie I don't have the right size screws in sufficient quantity to hand).

      It seems to me that max torque is being applied at four points, not two with a crosspoint. Granted they can "cam out" more easily, but that just requires technique to overcome. They also look better to me, a line of slotted screws doesn't look right if they aren't lined up, and that might not be possible, since that extra 1/4 turn might drive the screw too deep. Less of an issue with crosspoints in the first place, and only 1/8 turn required to straighten if it matters at all.

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      • #4
        Re: Screwdriver

        As for why we still have straight slotted fasteners...

        1) They are cheap to make
        2) Look better in some spots (say when exposed on a cabinet etc.)

        And although there are mechanically superior head designs today, slotted screws still provide pretty good turning power.

        Think about when driving in a slotted screw versus a phillips...yes, you have the problem of keeping the blade from sliding side to side with the slotted head, but it is not prone to "camming out" of the head. Phillips heads were actually designed to do just that. Cam out when you apply too much torque. (that's why you have to "lean" on your driver with a phillips at times).

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        • #5
          Re: Screwdriver

          >> "And although there are mechanically superior head designs today, slotted screws still provide pretty good turning power."

          Actually, I want to comment on this.

          First of all, in any of the smaller screw sizes, say, #8 or less - ANY of the common screw head styles is more than sufficient to twist the head off of the screw.

          Many of the problems people have with straight OR phillips head screws is due to the screwdriver. If you have a good straight screwdriver such as a SnapOn (and I understand that not everyone will have a $25 screwdriver) you will be amazed at how well it stays in the slot. With phillips, the problem is often that the screwdriver is a worn. Take a look at one sometimes... we often dion't notice but these things show quite a bit of wear.

          Some of the newer types of drives have some serious mechanical issues when used with flat head or oval head styles, though. And so they aren't really mechanically superior in all applications. Imagine a cross section of a flathead with either of these types of drives. Because the drive recess in the screw is straight-sided, the material left in the head gets very thin as you get deeper in to the recess. This is why some torx are sooooo shallow. If they were deeper, the material would be so thin that the head would crack. Another common thing that is done is that the torx or square drive will be made to a smaller size - say a T15 instead of a T20 - on flat heads than it really wants to be for the screw size - again, to leave a bit more "meat" in the head at the bottom corners of the recess. Just yesterday I was changing planer knives on my lunchbox planer and the torx DRIVER (supplied with the planer - probably chinese made with their excellent steel which sure didn't help) snapped right off while breaking the screw loose. Fortunately I had a "real" t25.

          The business about the thin material in flatheads is nothing new. We had the same issue with flatheads and hex (allen) drive. For thin sheetmetal work, we often used 100 degree flatheads - you never saw these with allen heads because the recess would have to be too shallow. The situation is much better with either straight or phillips.

          But there ARE plenty of applications where the newer drive types are a real advantage.

          My point is, nothing is perfect... a famous physicist named Anderson once said, "There is no problem, however complicated, which when you look at it the right way does not become still more complicated".

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          • #6
            Re: Screwdriver

            Originally posted by Andy_M View Post
            With phillips, the problem is often that the screwdriver is a worn. Take a look at one sometimes... we often dion't notice but these things show quite a bit of wear.
            Just yesterday I was changing planer knives on my lunchbox planer and the torx DRIVER (supplied with the planer - probably chinese made with their excellent steel which sure didn't help) snapped right off while breaking the screw loose. Fortunately I had a "real" t25.
            I had a Husky #2 Philips driver have the point shear off in a screw last weekend. Thankfully they replaced it at Home Depot, no questions asked, but it was quite striking how different the new head looked vs. the one with 6 years of use.

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            • #7
              Re: Screwdriver

              I would like to see someone come up with a tool to recondition Phillips head screwdrivers. Its such a waste to have to toss a screwdriver because the tip is in bad shape. Flat blade drivers could be reshaped several times with a grinding wheel or even a file.
              When seconds count, the police are only minutes away.

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