Broken tap or drill bit

Discussion in 'The Garage' started by Half Fast, Apr 19, 2013.

  1. Daryl_Stamp

    Daryl_Stamp Been here awhile

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    Cordless drill & tap works fast, but not for the faint of heart or first-timers or for that matter anyone that's not willing to extract a broken tap. However, that being said it's become my favorite method; ....... :) :) :)
    #21
  2. Ironwood

    Ironwood Friday Harbor, WA

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    As long as you don't tighten the chuck, it works well. But I always use a
    good cutting fluid.
    #22
  3. ohgood

    ohgood Just givver tha berries !!!

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    tap in a drill = broken tap. maybe not the first 5 times, but eventually, it will bite in an expensive part and you'll remember how many people said it was a bad idea.

    in a bridgeport, sure, tap a million holes. or with a fixture.

    what's really funny is seeing that apprentice 30 seconds after hearing the POW. the rest of his day is extracting, or begging for help extracting, that broken tap, while hiding from the owner.


    anyway, tap straight, careful, and patiently. :)
    #23
  4. Beezer

    Beezer Long timer

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    I brazed a old 1/4 drive socket on the top on a tap handle. it can be driven with a 1/4 drive T and extensions to suit
    #24
  5. Kommando

    Kommando Long timer

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    Yup...

    EDM, acid, tap extractor, spring-loaded centerpunch to shatter, carbide endmill....they all can work, depending on application.

    Avoid broken taps to begin with. If there is ANY doubt, use a brand-new HSS tapered tap (if there is enough depth) to start tapping, and a bottoming tap to finish. Brand-new HSS tapered taps cut SOOOOO easy, even into stainless. Use cutting fluid. Use the right tap-wrench for the job. Don't rush. Clear the chips. I barely dig in at all before I back it out and go in again. You can even use a slightly larger drillbit for the pilot hole. Even bits sold as the same size have slight differences. Measure the bits with calipers to be sure. You may find a looser size that is still appropriate.
    #25
  6. Ironwood

    Ironwood Friday Harbor, WA

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    Thats funny, I have done hundreds and never a broken tap. I can hold a drill steadier than I can a tap handle. Don't over tighten the chuck and you will be fine. If it starts to slip in the chuck, just reverse a a few turns and go in again. Fast and accurate.
    #26
  7. ohgood

    ohgood Just givver tha berries !!!

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    congratulations, you're the exception ! (zero sarcasm)
    #27
  8. Half Fast

    Half Fast Gnarly lurker

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    I'm with you. I got in the habit of only cutting about a quarter turn at a time then backing off to break and clear the chip. I've broken my share of taps over the years and the extra time it takes to do it slow is still faster than any extraction process. Often if the hole goes through and the material thickness is less than the diameter of the hole you can blast right through with a plug tap, probably even with a drill, no problem. Deeper bottoming holes are the ones that generally cause the problems.

    The bottom line is that you have to break some taps to get a feel for the kind of torque you can get away with!

    Again, thanks to all for the "tips on taps".

    .
    #28
  9. Twin-shocker

    Twin-shocker Long timer

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    Not breaking tap in the first place is obviously the best way to avoid needing to remove a broken one. However if a tap does break, then in most cases anyone with a MIG welder can remove it easily.

    The technique involves building up a blob of weld on the broken tap, big enough to grip with a mole wrench, then turning out the tap as soon as the weld has cooled from red heat. This also works on broken bolts, and is far easier and less costly that almost all of the methods outlined here.
    #29
  10. Daryl_Stamp

    Daryl_Stamp Been here awhile

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    My brother got some help on his diesel with that 'weld it out technique'; was pretty cool, but don't recall the term 'mole wrench', had to use wiki to learn that it is a 'vise grip'.
    #30
  11. sailah

    sailah Lampin' it

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    I agree with this method I tap holes ALL THE TIME using this same method. Haven't broken a tap in over a decade.

    Drill the correct hole, use plenty of cutting fluid and don't reef down on the chuck. It's almost foolproof. I use the same method tapping smaller holes on the lathe. The grip on the tap depends on a bunch of different factors but not tightening the chuck all the way acts as a clutch.

    I probably tap 95% of my holes using a chuck either in the lathe, drillpress or cordless drill.
    #31
  12. P B G

    P B G Long timer

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    I do this as well, so long as the hole is drilled well,

    So many drill/drivers have torque clutches and low/high speed. On low with the slipper a few clicks off "drill" seems to work well on large taps, otherwise I start at loose on the clutch and move up.
    #32
  13. LuciferMutt

    LuciferMutt Rides slow bike slow

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    I've had limited success with only two methods:

    -shattering the tap with a center punch, then picking/blowing out the remains

    -fishing a piece of stiff but thin wire into each flute, then grabbing the protruding ends of the wire with a pair of linemans as close to the surface as possible and twisting it back and forth. This is the poor mans tap extractor. The real tap extractors have never worked for me!

    Beyond that, take the part somewhere with an EDM tap burner and have it vaporized. :lol3 Small, special EDMs specifically for removing broken taps/drills are sold. My trade school shop had an ancient one...it wasn't even called an EDM, but an arc something or other...can't remember.
    #33