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how do you use small taps?

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  • how do you use small taps?

    I have to tap 6 8NC32 holes, about 3/4" deep. My tap broke three times and I had to extract the broken fragment twice with a dremel (I've interest in removal the third time). I was tapping in the small drill-press with the spring of the spindle completely dis-engaged (the one that pulls the spindle up). I was going real slow and backing out the chips every 1/4 turns.

    The tap is CHINESE.

  • #2
    Originally posted by Elninio
    I have to tap 6 8NC32 holes, about 3/4" deep. My tap broke three times and I had to extract the broken fragment twice with a dremel (I've interest in removal the third time). I was tapping in the small drill-press with the spring of the spindle completely dis-engaged (the one that pulls the spindle up). I was going real slow and backing out the chips every 1/4 turns.

    The tap is CHINESE.
    First off, why would you ever try to tap an 8-32 hole 3/4" deep? The old rule is maximum holding power is attained at 1 1/2 times the diameter of the tap. For an 8-32 that would be something less than 1/4" depth.
    Second off, using Chinese taps for any kind of deep hole tapping is a real mistake.

    Back bore your holes, so that you only have to tap 1/4" deep,and you will be fine.
    I am not young enough to know everything

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    • #3
      Which tap are you using? You need to start the hole and go as far as you can with a taper tap then use a plug tap, the taper tap will cut with much less resistance and is a lot easier to use without breaking. It seems taper taps are hard to find at most stores and usually plug taps are all most places have, some of them do have bottom taps sometimes, but for whatever reason plug types are the most common.

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      • #4
        I use Chinese taps to fill in unwanted holes. Simply crank the sucker in, snap it off and grind flush.


        Seriously... Don't waste your time with that junk. You can follow proper tapping process but it's all for naught if you use junk "Snap-Off(tm)" taps.
        This product has been determined by the state of California to cause permanent irreversible death. This statement may or may not be recognized as valid by all states.
        Heirs of an old war/that's what we've become Inheriting troubles I'm mentally numb
        Plastic Operators Dot Com

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        • #5
          Originally posted by BMSS

          Back bore your holes, so that you only have to tap 1/4" deep,and you will be fine.
          How do you back bore a blind hole.... Especially on a hole that small?
          Feel free to put me on ignore....

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          • #6
            BMSS & Liger are spot on.

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            • #7
              Originally posted by daveo
              How do you back bore a blind hole.... Especially on a hole that small?
              He never said anything about them being a blind holes. Guess you read something that I didn't.
              I am not young enough to know everything

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              • #8
                How do you know if a tap is 'Snap-Off' brand?

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                • #9
                  Originally posted by Elninio
                  How do you know if a tap is 'Snap-Off' brand?
                  My pet nickname for junk Chinese tools.
                  This product has been determined by the state of California to cause permanent irreversible death. This statement may or may not be recognized as valid by all states.
                  Heirs of an old war/that's what we've become Inheriting troubles I'm mentally numb
                  Plastic Operators Dot Com

                  Comment


                  • #10
                    Originally posted by Liger Zero
                    My pet nickname for junk Chinese tools.
                    I know - but not all taps are advertised as MADE IN USA or something like that

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                    • #11
                      If your tapping a hole more than 2x's the diameter in depth the tap drill size can be increased since you will have more threads engaged.The increase in tap drill size means a slightly larger hole and a reduction in the amount of torque required to thread it.
                      I just need one more tool,just one!

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                      • #12
                        Originally posted by Elninio
                        I know - but not all taps are advertised as MADE IN USA or something like that
                        To be fair I've had American and French made taps snap off on me. That was mostly my fault as I was still learning how to use them properly. "Cranky Old Machinist In The Corner" showed me the right way... after he bit my head off for ruining his expensive French tap. (I paid to replace it out of my pocket A) because he took the time to teach me the right way and B) that's just how I roll. I break it I replace it.)


                        I had a set of Chinese Taps I got at a flea-market. Complete with Chinese paperwork! They were less than useless for metal I broke most of the smaller diameter ones.
                        This product has been determined by the state of California to cause permanent irreversible death. This statement may or may not be recognized as valid by all states.
                        Heirs of an old war/that's what we've become Inheriting troubles I'm mentally numb
                        Plastic Operators Dot Com

                        Comment


                        • #13
                          Originally posted by Elninio
                          I know - but not all taps are advertised as MADE IN USA or something like that
                          They don't have to be made in USA to be good and not all US made taps are good.

                          Some brand names to look for-OSG,Nachi,Greenfield,TRW,TMX,Excello.

                          High Speed steel is best for longevity and for my own personal preference 3 flute taps work best for me when hand tapping,especially spiral point "gun" taps.
                          I just need one more tool,just one!

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                          • #14
                            Why do the chinese tap suck more --- do they start with a weaker metal, or do they get the heat-treatment wrong?

                            Comment


                            • #15
                              Originally posted by wierdscience
                              They don't have to be made in USA to be good and not all US made taps are good.

                              Some brand names to look for-OSG,Nachi,Greenfield,TRW,TMX,Excello.

                              High Speed steel is best for longevity and for my own personal preference 3 flute taps work best for me when hand tapping,especially spiral point "gun" taps.
                              Are those brands to watch out for in a negative way? Or as those brand I would want to buy? Do they make taps out of carbide?

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