I just came across this bit in my toolbox, which I'm fairly sure came with an installers drill bit (54" long flexible bit, with a hole in the end for pulling wires back through).

mystery bit

It's a standard screw driver bit, tapered at the end (though not enough to actually be a flathead bit) and a hole through it. Any ideas what this is for?

6 Answers 6


I think it would be used for pulling or twisting something. For example, you would attach a wire to it, then engage the drill or manually rotate, thus twisting or rotating the wire. It would also be used for fishing the wire thought a wall. The rotation would allow it to more easily pass.


If you hadn't said it came with the installer's bit, I would have guessed it was for twisting safety wire:

Safety wire

I guess it's still possible, but it seems like an unlikely thing to include with an installer's bit.


Can't say for sure, but I would say it's for twisting pairs/groups of wires together.


It can be adapted to many uses but its main intended purpose is to drive threaded cup hooks and similar fittings into their pilot holes.


Maybe you're meant to push something like a screwdriver through the hole, and then use that as a handle (lots of leverage). Of course this could damage your screwdriver if you weren't careful...


ive been looking for that piece for awhile, not sure what the real purpose of it is but I use it to put a twist in the phone wires at work. that piece did come with a fish net looking contraption but I toss it just use as a wire twister cause it snap into the drill easily.

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