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  1. #1
    Ueee's Avatar
    Ueee is offline Blacksmith, Cabinetmaker, Machinist, Messmaker
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    Default Dangers of breaking taps *GRAPHIC IMAGES*

    Hi Guys,
    I've been a little quiet of late but i think this one is one of those eye openers i had to share.

    I've been working from home part time (4 days a week) for over a year now, mostly on knifemakers tools and equipment.
    For all my tapping i use a piper tapping chuck in the Hercus camelback, it is a great paring.

    I try to avoid blind holes due to the risks of bottoming out the tap, and when i do i try to leave a decent amount of clearance. There are times however it cannot be avoided.

    On Wednesday i was tapping M6, and i had to get as much thread as i could in the holes (about 150 of them, so hand tapping was not a really viable option) as i only had 12mm of material thickness.

    Despite drilling them in the mill one hole must have been shallow, and inevitably the tap (spiral flute HSS-E Dormer) bottomed out and "exploded".

    A piece hit me on the inside of the elbow, and i heard a few hitting things behind me. Ouch, get over it, move on!

    Fast forward to today with a nice yellow bruise and hard lump. Surely there is not a bit in there?

    A test with an N50 neodymium magnet soon proved me wrong. Pictures show the rest!

    I tend to be a bit lax some days with my safety glasses. It's only drilling and tapping right, what could happen? Not any more!

    Cheers,
    Ew
    Attached Images Attached Images
    1915 17"x50" LeBlond heavy duty Lathe, 24" Queen city shaper, 1970's G Vernier FV.3.TO Universal Mill, 1958 Blohm HFS 6 surface grinder, 1942 Rivett 715 Lathe, 14"x40" Antrac Lathe, Startrite H225 Bandsaw, 1949 Hercus Camelback Drill press, 1947 Holbrook C10 Lathe.

  2. #2
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    A vivid warning to take heed of Ew. Thankfully it was your elbow and not an eyeball.

    And it is great to hear from you again. I and I'm sure others have missed your presence on the forum.

    BT

  3. #3
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    OUCH! Glad its out and you - and me - have learnt a lesson....
    Cheers, Joe
    retired - less energy, more time to contemplate projects and more shed time....

  4. #4
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    Wow, who would have thought that a fragment from a desintergrating tap would have the momentum or energy to embed in the skin.

    Ouch!

    Nice photos though! Thanks for posting.

    Simon
    Girl, I don't wanna know about your mild-mannered alter ego or anything like that." I mean, you tell me you're, uh, super-mega-ultra-lightning babe? That's all right with me. I'm good. I'm good.

  5. #5
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    Quote Originally Posted by simonl View Post
    Wow, who would have thought that a fragment from a desintergrating tap would have the momentum or energy to embed in the skin.
    Once saw a pheasant that had never thought tiny lead balls had the momentum or energy to penetrate its skin. Wasn't over it yet when it was laying on my plate beside the sauerkraut......
    I am sure the mass of one of these balls was less then the mass of the tap fragment.
    Not saying it couldn't have happened to me, just that basic protection is our only line of defense against these "freak" accidents. I have a set of prescription safety glasses that makes it easy to almost always wear safetyglasses in the shop. Advantage for us lucky bastards that need glasses anyway Dangers of breaking taps *GRAPHIC IMAGES*

    Ueee, glad it turned out only to be a painfull learning experience! Hope you heal soon.

    Peter

  6. #6
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    Can't remember what sort of grass (weed) it was, but it grew in clumps, with long stalks and sometimes using a brusshcutter, the stalks would penetrate the jeans I was wearing and embed them quite deeply into the skin on my legs and occasionally other places. So, it's not just the hard metal or other stuff to be aware of. Anything travelling at speed can do you damage.
    Nev.

  7. #7
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    Glad you are ok. Could have been worse as I'm sure you are aware.
    Many years ago (35+), where I worked had a couple of reversible tapping chucks that had adjustable clutches in them. You adjusted the clutch so it only just drove the tap. If it bottomed out the clutch would slip before the tap broke. I can't remember what brand they were though. Possibly a Piper?

    peter

  8. #8
    Ueee's Avatar
    Ueee is offline Blacksmith, Cabinetmaker, Machinist, Messmaker
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    Quote Originally Posted by bollie7 View Post
    Glad you are ok. Could have been worse as I'm sure you are aware.
    Many years ago (35+), where I worked had a couple of reversible tapping chucks that had adjustable clutches in them. You adjusted the clutch so it only just drove the tap. If it bottomed out the clutch would slip before the tap broke. I can't remember what brand they were though. Possibly a Piper?

    peter
    I have seen those ones, but have never seen one that is not either a cheap knockoff (H&F sells them) or really expensive. It would be nice to have one but normally it should not be a problem!
    1915 17"x50" LeBlond heavy duty Lathe, 24" Queen city shaper, 1970's G Vernier FV.3.TO Universal Mill, 1958 Blohm HFS 6 surface grinder, 1942 Rivett 715 Lathe, 14"x40" Antrac Lathe, Startrite H225 Bandsaw, 1949 Hercus Camelback Drill press, 1947 Holbrook C10 Lathe.

  9. #9
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    Hi Ew,

    Glad you are ok, and thanks for the safety reminder.

    Ray

  10. #10
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    An older chap I know was flattening out the curved edge of a drum with a sledge hammer underneath the drum edge and was hitting the edge of the drum with a normal hammer. He missed one hit and the two hammer collided, and a piece spalled off and went through his penis. Had to go to the hospital emergency room, x ray and everything. Apparently it was painful and his wife said it was very funny.
    Gold, the colour of choice for the discerning person.

  11. #11
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    Ueee, out of interest what RPM were you tapping the M6 holes?

    Simon

    Actually I has just occured to me that it wouldn't be the RPM of the tapp that created the sufficient projectile speed to penetrate the skin. I was most likely the energy released from the fracturing of the HSS after undergoing some form of torsional flex?

    I guess a huge amount of energy can be imparted on a very small part, giving rise to very high velocities.

    Simon
    Girl, I don't wanna know about your mild-mannered alter ego or anything like that." I mean, you tell me you're, uh, super-mega-ultra-lightning babe? That's all right with me. I'm good. I'm good.

  12. #12
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    Default safety

    Glad you are OK Ewan .

    Changing topics. I am always very aware of bench grinding wheel safety. At TAFE they showed us a old movie on grinding wheel safety , made in the 1950's . The wheels have been known to explode/disintegrate and you don't want to be anywhere nearby when it happens .

    I always use new grinding wheels on the bench grinder, I don't trust used wheels . I have one of those full face masks I use when grinding . Mike

  13. #13
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    so did you turn up at the doc with the magnet stuck to your skin
    regards from Canmore

    ian

  14. #14
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    good message there for me Ueee

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