A collection of drill bits contains three elements like the one in the picture below. It's about 30mm high. 15mm outer diameter, and marked "ADW". Internally it contains a spring with some flexible metal protrusions at the one end. What is its use?

Drill-set accessory

In the complete set they are located on the right of four flat donut-shaped bits (also of unknown purpose), each containing an Allen screw to fix them on an axis.

Complete drill set — side 1

Complete drill set — side 2

  • Some form of ratchet?
    – keshlam
    Jan 14, 2023 at 13:51
  • 1
    I had an old drill bit sharpener that had a drill bit holder that looked a tiny bit like that, but if similar then pieces are missing. Does the tool turn? Can you twist the bottom and top sections?
    – crip659
    Jan 14, 2023 at 15:25
  • @Ecnerwal I added a picture of the complete set. The other end is round (as shown in the second picture). Jan 14, 2023 at 17:50
  • @crip659 The tool's outside is a single piece of plastic; it doesn't turn. Jan 14, 2023 at 17:51
  • 6
    "four flat donut-shaped bits (also of unknown purpose), each containing an Allen screw to fix them on an axis." Those are depth stop collars. They clamp to a suitable sized drill bit so you can drill a hole of a certain depth, but no more (unless they slip...)
    – Ecnerwal
    Jan 14, 2023 at 17:55

1 Answer 1


The black donuts are depth gauges, they go over the drill bits so you can drill holes to preset depth.

The blue things are screw holders I think, to hold screws against the driver bits.

  • 1
    I believe you're quite correct on the blue thing. You put a screwdriver bit in the drill, slip this over the end, then put the screw into the blue holder. Put the tip of the screw where you want it to go, and hold the blue collar while starting the screw. This allows you to hold the non-spinning blue collar, and it holds the spinning screw & driver bit for you.
    – FreeMan
    Jan 16, 2023 at 15:43
  • Thanks! I tried it, and it seems to work in this way. All three screw holders are for the same size screws. It would have been more useful to have three different diameters for corresponding screws. Jan 16, 2023 at 21:46
  • I'm glad you found those useful, @DiomidisSpinellis, I've never been able to make one work in any sort of meaningful way. Maybe it's just me...
    – FreeMan
    Jan 17, 2023 at 14:16
  • Whan I wrote it "worked" I meant that piecing together the various elements gave me an assembly might do the intended job. I've yet t use it for actually drilling. Jan 18, 2023 at 17:41

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