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Amazon is selling the Greenlee Textron #DTAP1/4-20 1/4-20 Hex/Tap Bit for $3.98 right now.

I hadn’t noticed these tools before — the Greenlee Hex/Tap Bits are combined drills with taps and a countersink with a hexagonal shank to fit in a drill/driver. You can read the .pdf for full details. The bit drills the proper-size tap hole, then taps the thread and chamfers the hole. The only thing that puzzles us is that they are rated for 10 ga. metal only, which seems thin given that the range of sizes goes up to 5/16-18′. With a 1/4″-20 tpi you would only get about two threads of engagement in metal that thin. We can’t see any reason they wouldn’t work in thicker metal, so it’s somewhat puzzling. It does seem like the sort of tool that would speed up fabrication projects.

Via Amazon [What’s This?]


7 Responses to Dealmonger: Greenlee Textron Hex/Tap Bit

  1. Brice says:

    You could probably get away with slightly thicker metal for the bigger bits, but the threads will just tear out of the bit can’t feed fast enough.

  2. David Bryan says:

    MSC and Tapco USA have them up to 1/2 inch or 1″” pipe size. Alfatools.com shows them up to 5/8 inch. I like these but they’re something I’d just as soon buy at Harbor Freight and get a black box instead of a nice green one. I also like the tapdrivers you used to find at Sears, and I used to carry a long no. 21 drill and a 10-32 tap to put a hole for a ground screw into old electrical boxes, but I use these now. The 6-32 ones break pretty easy. I say get ’em cheap and don’t expect miracles.

  3. fred says:

    ICS and other sell gun taps, spiral point taps and combined drill/taps. Machine tapping by (unsteady) hand often results in a broken tap.
    Here is a link that may be of interest:


  4. philip says:

    love these things, i do a lot of repeat holes in metal back panels and helps reduce time.

  5. Jupe Blue says:

    I love them too. I do keep spare drill bits of the appropriate size so when the tip of the gets dull, I can still use the tap.

  6. Nick says:

    I use these quite a bit and they are damn handy. I’m an electrician and I use them quite often for low voltage panels.

    Only problem is they aren’t very tough hence the thin metal only. I’ve taken them through 1/8″ steel but not more than once and after repeat usage they do tend to get brittle and break.

    The countersink is great for de-burring but the drill tip is so-so. Like most drill bits, the last 5% is where they snap the most but if you make it all the way through, I’ve never had it snap while threading.

  7. They are useful and I use them quite often.

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