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Re: [multimachine] Cleaning chips from a blind tapped hole.

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  • Bruce Bellows
    I ve had to tap holes in air and hydraulic cylinder bodies before and that s where you really need the ability to control metal chips to prevent them from
    Message 1 of 7 , Feb 6, 2010
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      I've had to tap holes in air and hydraulic cylinder bodies before and that's where you really need the ability to control metal chips to prevent them from entering the cylinder where they can destroy the inner walls and seals. The method that I've always used is to pack the tap with grease that will keep the chips in the flutes, note there aren't big chips when tapping a NPT thread. Regarding tapping blind holes, avoid blind holes whenever possible, drill a through hole even if only the top half is tapped. On stock 1" or less in thickness I always drill a through hole unless the location of the backside of the hole would cause a problem. Also once a tap starts to dull it goes to the garbage, doing this will minimize broken taps and the consequences of a broken tap far outweigh the cost of the tap.
       
      Bruce
       
      ----- Original Message -----
      From: RRR
      Sent: Friday, February 05, 2010 7:40 PM
      Subject: [multimachine] Cleaning chips from a blind tapped hole.

       

      I suppose that most members are aware of using plasticine clay to "float" chips out of a hole when taping threads, but it is worth repeating if the knowledge prevents even one broken tap.  They are so difficult to remove, especially should the tap jam on a chip and snap off below the surface of the workpiece.

    • smiterfe
      Thanks for the tips. Worth their weight...
      Message 2 of 7 , Feb 7, 2010
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        Thanks for the tips. Worth their weight...
      • Ian Newman
        Hi, Most non-professional drawings often specify tapped holes that are far too deep - this not only increases the amount of work done, but also increases the
        Message 3 of 7 , Feb 8, 2010
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          Hi,

          Most non-professional drawings often specify tapped holes that are far too deep - this not only increases the amount of work done, but also increases the risk of broken taps.

          Under normal conditions the depth of the threaded part of a hole never needs to be more than 1.5 times the diameter of the bolt (take a look at the depth of a standard nut).

          Ian.

          --- On Sat, 6/2/10, Bruce Bellows <bbellows@...> wrote:

          From: Bruce Bellows <bbellows@...>
          Subject: Re: [multimachine] Cleaning chips from a blind tapped hole.
          To: multimachine@yahoogroups.com
          Date: Saturday, 6 February, 2010, 17:31

           

          I've had to tap holes in air and hydraulic cylinder bodies before and that's where you really need the ability to control metal chips to prevent them from entering the cylinder where they can destroy the inner walls and seals. The method that I've always used is to pack the tap with grease that will keep the chips in the flutes, note there aren't big chips when tapping a NPT thread. Regarding tapping blind holes, avoid blind holes whenever possible, drill a through hole even if only the top half is tapped. On stock 1" or less in thickness I always drill a through hole unless the location of the backside of the hole would cause a problem. Also once a tap starts to dull it goes to the garbage, doing this will minimize broken taps and the consequences of a broken tap far outweigh the cost of the tap.
           
          Bruce
           
          ----- Original Message -----
          From: RRR
          Sent: Friday, February 05, 2010 7:40 PM
          Subject: [multimachine] Cleaning chips from a blind tapped hole.

           

          I suppose that most members are aware of using plasticine clay to "float" chips out of a hole when taping threads, but it is worth repeating if the knowledge prevents even one broken tap.  They are so difficult to remove, especially should the tap jam on a chip and snap off below the surface of the workpiece.


        • Bruce Bellows
          Ian, you re absolutely right and I ve often tapped a hole from each side of a thick piece of metal for bolting onto both sides rather that risk breaking a tap
          Message 4 of 7 , Feb 8, 2010
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            Ian, you're absolutely right and I've often tapped a hole from each side of a thick piece of metal for bolting onto both sides rather that risk breaking a tap trying to go all the way through. Only with a CNC and lots of coolant can deep tapped holes be done with confidence and even then shit happens.
             
            Bruce
              
            ----- Original Message -----
            Sent: Monday, February 08, 2010 8:43 AM
            Subject: Re: [multimachine] Depth of tapped holes - was Cleaning chips from a blind tapped hole.

             

            Hi,

            Most non-professional drawings often specify tapped holes that are far too deep - this not only increases the amount of work done, but also increases the risk of broken taps.

            Under normal conditions the depth of the threaded part of a hole never needs to be more than 1.5 times the diameter of the bolt (take a look at the depth of a standard nut).

            Ian.

            --- On Sat, 6/2/10, Bruce Bellows <bbellows@rogers. com> wrote:

            From: Bruce Bellows <bbellows@rogers. com>
            Subject: Re: [multimachine] Cleaning chips from a blind tapped hole.
            To: multimachine@ yahoogroups. com
            Date: Saturday, 6 February, 2010, 17:31

             

            I've had to tap holes in air and hydraulic cylinder bodies before and that's where you really need the ability to control metal chips to prevent them from entering the cylinder where they can destroy the inner walls and seals. The method that I've always used is to pack the tap with grease that will keep the chips in the flutes, note there aren't big chips when tapping a NPT thread. Regarding tapping blind holes, avoid blind holes whenever possible, drill a through hole even if only the top half is tapped. On stock 1" or less in thickness I always drill a through hole unless the location of the backside of the hole would cause a problem. Also once a tap starts to dull it goes to the garbage, doing this will minimize broken taps and the consequences of a broken tap far outweigh the cost of the tap.
             
            Bruce
             
            ----- Original Message -----
            From: RRR
            Sent: Friday, February 05, 2010 7:40 PM
            Subject: [multimachine] Cleaning chips from a blind tapped hole.

             

            I suppose that most members are aware of using plasticine clay to "float" chips out of a hole when taping threads, but it is worth repeating if the knowledge prevents even one broken tap.  They are so difficult to remove, especially should the tap jam on a chip and snap off below the surface of the workpiece.


          • o1bigtenor
            Do your tapping using thread milling - - much better!!! D ... Do your tapping using thread milling - - much better!!! D On Mon, Feb 8, 2010 at 9:08 PM, Bruce
            Message 5 of 7 , Feb 9, 2010
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              Do your tapping using thread milling - - much better!!!

              D

              On Mon, Feb 8, 2010 at 9:08 PM, Bruce Bellows <bbellows@...> wrote:
              


              Ian, you're absolutely right and I've often tapped a hole from each side of a thick piece of metal for bolting onto both sides rather that risk breaking a tap trying to go all the way through. Only with a CNC and lots of coolant can deep tapped holes be done with confidence and even then shit happens.
               
              Bruce
                
              ----- Original Message -----
              From: Ian Newman
              Sent: Monday, February 08, 2010 8:43 AM
              Subject: Re: [multimachine] Depth of tapped holes - was Cleaning chips from a blind tapped hole.

               

              Hi,

              Most non-professional drawings often specify tapped holes that are far too deep - this not only increases the amount of work done, but also increases the risk of broken taps.

              Under normal conditions the depth of the threaded part of a hole never needs to be more than 1.5 times the diameter of the bolt (take a look at the depth of a standard nut).

              Ian.

              --- On Sat, 6/2/10, Bruce Bellows <bbellows@...> wrote:

              From: Bruce Bellows <bbellows@...>
              Subject: Re: [multimachine] Cleaning chips from a blind tapped hole.
              To: multimachine@yahoogroups.com
              Date: Saturday, 6 February, 2010, 17:31

               

              I've had to tap holes in air and hydraulic cylinder bodies before and that's where you really need the ability to control metal chips to prevent them from entering the cylinder where they can destroy the inner walls and seals. The method that I've always used is to pack the tap with grease that will keep the chips in the flutes, note there aren't big chips when tapping a NPT thread. Regarding tapping blind holes, avoid blind holes whenever possible, drill a through hole even if only the top half is tapped. On stock 1" or less in thickness I always drill a through hole unless the location of the backside of the hole would cause a problem. Also once a tap starts to dull it goes to the garbage, doing this will minimize broken taps and the consequences of a broken tap far outweigh the cost of the tap.
               
              Bruce
               
              ----- Original Message -----
              From: RRR
              Sent: Friday, February 05, 2010 7:40 PM
              Subject: [multimachine] Cleaning chips from a blind tapped hole.

               

              I suppose that most members are aware of using plasticine clay to "float" chips out of a hole when taping threads, but it is worth repeating if the knowledge prevents even one broken tap.  They are so difficult to remove, especially should the tap jam on a chip and snap off below the surface of the workpiece.





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