Worn Tap Broken

Discussion in 'Mistakes, Blunders and Boo Boos' started by Ghosty, Nov 20, 2016.

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  1. Nov 20, 2016 #1

    Ghosty

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    Had to remake a case after the tap broke off in the last hole. I build and run RC boats so I use a lot of stainless parts, wears taps out quickly.

    Cheers

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  2. Nov 20, 2016 #2

    Hopper

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    Ouch. Yes it is always taht last hole that the tap seems to break off in for some reason.
     
  3. Nov 20, 2016 #3

    stragenmitsuko

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    As a last resort , I've managed to remove broken taps on occasion with one of these . With a ball nose end that is , not tapered ones .

    Don't know what they are called in english .

    Pat

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  4. Nov 21, 2016 #4

    Cogsy

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    One of these days I need to source some Alum off the net (not available in the supermarkets I've looked in here) so if/when I break a drill or tap in a critical non-ferrous part I can have a go at dissolving it out.
     
  5. Nov 21, 2016 #5

    goldstar31

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    I was discussing nail biting and finger sucking with my son. My little grand daughter has finally stopped. I said that alum was once used.
    The most available source is for cuts with open razors called a 'styptic pencil' which is alum.

    Hope this helps

    Norman
     
  6. Nov 21, 2016 #6

    mcostello

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    Just to let You know, I tried the Alum trick on a tap and did not have any success with it. Some taps are immune to it. I put the part in a dish and left it on a warm woodstove for a week with no discernible difference.
     
  7. Nov 21, 2016 #7

    canadianhorsepower

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  8. Nov 22, 2016 #8

    Ken I

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    I have always had success removing broken taps with Alum (Aluminium Sulphate) available from swimming pool supply shops.

    (It's used as a flocculant / clarifier for swimming pools.)

    Make a super saturated solution in an aluminum pan and keep it boiling at 100 - 120°C - tap's gone in 1 to 3 hours.

    You can't just let is soak and you have to keep topping up to replace the water loss.

    Let the temperature fall below 100°C before adding water otherwise it can blow up in you face.

    If you can drill a weep hole below the broken tap - this allows the liquid to "circulate" and speed up the time to disove the tap.

    Its fiddly and time consuming (you have to keep a close eye on it).

    It doesn't seem to remove (much ?) metal from non-ferrous materials but it does make the surface dull - but that cleans up easily enough.

    Regards,
    Ken
     
  9. Nov 22, 2016 #9

    mcostello

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    Replaced the water loss for a week,simmering much of the time.
     
  10. Nov 23, 2016 #10

    SmithDoor

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    Try Automotive machine shop
    Most have EDM machine for remove bolts and taps may not be low cost but will get tap out or low cost hammer and punch will take time.

    Good Luck:thumbup:
    Dave

     
  11. Dec 22, 2016 #11

    Shipdisturber

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    Problem with stainless is it galls or packed into the tap flutes then you basically won't get the tap safely out. Lots of lube and patience is the only way to tap stainless for me, I don't know how many stainless bolts etc I screwed up before I figured this out.
     
  12. Jan 25, 2017 #12

    machineman8625

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    The best way to remove broken taps is don't break them. DO NOT USE CARBON TAPS. They are like peanut brittle and snap off if you look at them wrong. Use HSS or cobalt
     
  13. Jan 25, 2017 #13

    Blogwitch

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    Machine,

    Don't write off carbon taps and dies, I have been using them for stainless threading for many years and never had one break.

    What you have to remember is that there are carbon taps and CARBON TAPS. The ones I use are a lot more expensive than your general HSS ones, and I even have a metric set up to 6mm that must be 30 years old by now, and still going strong.

    I won't use anything else on stainless.

    John
     
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  14. Jan 26, 2017 #14

    canadianhorsepower

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  15. Jan 26, 2017 #15

    Blogwitch

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    Al, if you are going to make a habit of building more little engines or breaking taps off down holes, or even wanting funny shaped holes boring through some metal, then maybe you should consider a spark erosion machine.

    I put the plans for one here in the downloads section many moons ago.

    http://www.homemodelenginemachinist.com/downloads/cheap-and-easy-to-make-spark-eroder-240.html

    It was about 10 years ago when the plans and article were first introduced to the world (not by me BTW), so expect the cost for the raw materials to have doubled in that time. But still worth the overall outlay.
    I have never made one, as I had a friend who took anything like that into work for me to have the weird shaped holes put through parts (machine was used to put holes into jet engine guide vanes for fuel and cooling), but now he has retired, maybe I should be looking at making one for myself.

    John
     
  16. Jan 27, 2017 #16

    Shipdisturber

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    In Canada we call them a Burr
     
  17. Apr 8, 2017 #17

    vintagengineer

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    You can resharpen your taps by grinding the flutes
     
  18. Apr 11, 2017 #18

    bananabearings

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    what taps and dies do you use please John - are they still available to buy
    thanks,
    David
     
  19. Apr 11, 2017 #19

    Blogwitch

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    Hi John,

    For most of my taps and dies I use these people.

    http://www.tapdie.com/

    Rather expensive for what they are, but they cut through stainless as though it was just brass or aluminium. Over the years I have managed to get complete boxed sets for all the threads I am liable to use.

    John
     

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