What kind of bit is needed for this screw?

Original image of screw in yoke

A Phillips bit does not make it and a straight blade either.

(I feel that whoever came up with this idea should be covered in honey and placed in an ant mound.) :-)

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The bit on the right fit that screw the best.

I went looking thru my screw drawers to find a replacement of better design.

Those screws are like fruit flies. They are everywhere.

  • 1
    Looks like a flat blade screw driver would work in the slot. The center would probably accept one size of square drive. Dec 23, 2022 at 0:15
  • 2
    No matter what driver bit is used, guys will continue to strip out the screw heads by inappropriate use of power drivers, especially impact drivers.
    – kreemoweet
    Nov 14, 2023 at 13:35

4 Answers 4


A medium size flat-head screwdriver should work fine.

But the preferred usual choice is a Robertson square drive.

And the absolute best is a combination, such as this Klein:

Klein combination tip screwdriver

I have various Klein tools, I do not have this one, I have no stock in them. This is just the first example I found on Amazon showing this type of tip. My electrician uses the Robertson square drive, and most of the time I just pick up a regular screwdriver.

Some of these are actually designed with a little extra slot perpendicular to the main slot, so that a Phillips will work to a reasonable degree, but the one you pictured here does not appear to have that.

  • 3
    The tip shown on the screwdriver, looks more like a Torx drive.
    – crip659
    Dec 23, 2022 at 0:21
  • 1
    I added some more clear pictures.
    – fixit7
    Dec 23, 2022 at 3:07
  • 4
    Based on the original image which shows this as a typical yoke screw, the Klein tool (or similar from other manufacturers) which is a combination Robertson or square + flat is the correct tool for the job. Probably #2, but I'm not sure - they often come as a set of #1 and #2 anyway. Either order something off Amazon or take one of the screws to your local hardware store or Home Depot/Lowes/etc. and you can try a combination screwdriver bit in the store to make sure it is the right thing. Except be warned that nothing will fit 100% once the square part gets messed up. Dec 23, 2022 at 4:25
  • 2
    … Actually, I'm now pretty certain that it's a Torx, since I did a Google reverse image search and found this image that clearly shows the exact same product photo — slightly rotated but otherwise identical down to the reflections on the shaft — but calls it a Torx. I guess whoever made the image also got confused by the similarity and picked the wrong product photo. Dec 23, 2022 at 15:55
  • 2
    Image or not, ecx is not the same as torx. Dec 23, 2022 at 19:39

That screw will take either a flat blade or a robertson(think #2), (American square) screwdriver.

If flat blade does not work then you need a larger one.

Robertson's were invented to prevent flats from cutting screw driver's hands when they slipped.


Pretty sure its called an ECX bit. It fits perfectly. However, it is a robertson in the center and you could use that instead and it works just as well.

  • Hi Huy, a citation would improve your answer. Nov 14, 2023 at 9:58
  • A Robertson/square drive will work in a pinch, but just not quite.
    – FreeMan
    Nov 14, 2023 at 14:06
  • @RohitGupta citations in the comments on manassehkatz's answer. Loads of people there agreeing, as do I.
    – FreeMan
    Nov 14, 2023 at 14:07

Flat, Phillips, square. Use the square, probably a number one which is the small one.

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