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  • roughing cuts

    I am getting chater when takeing 0.80 thou cuts in bright bar. any way to stop it?

  • #2
    Turning? Milling?
    .800 per pass?
    I hope you meant .080
    RPM? Feedrate?

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    • #3
      Turning? Milling? Turning
      .800 per pass? 80 thou per pass
      RPM? Feedrate? 250 rpm feed= .046 inch/rev

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      • #4
        HSS or Carbide?

        Carbide likes deeper and faster.

        Are your gibs snug?
        Cheers,
        Gary

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        • #5
          That must be a very strong lathe to take .080" on a side at 250 rpm with a feed of .046" per revolution.
          It's only ink and paper

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          • #6
            What is a "bright bar"? I've machined lots of steel, stainless steel, cast iron, non-ferrous metals, plastics, ceramics and composites, none were referred to as "bright bar".

            Is that a local term for aluminum or something?

            Wow....046" per rev! My lathe tops out at 1/2 that, and it's 5HP. You're pulling a lot of HP with a feed like that. Right there could be a source of chatter.

            The depth of cut and spindle speed mean little without knowing diameter, workpiece and tool materials. It's all about SFM rates.
            Last edited by PixMan; 09-04-2011, 10:37 PM.

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            • #7
              What's the diameter of the workpiece?

              Larger diameter will need slow speeds, small diameter needs increasing speeds to keep your SFM up.
              Cheers,
              Gary

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              • #8
                Originally posted by PixMan
                What is a "bright bar"? I've machined lots of steel, stainless steel, cast iron, non-ferrous metals, plastics, ceramics and composites, none were referred to as "bright bar".

                Is that a local term for aluminum or something?

                Wow....046" per rev! My lathe tops out at 1/2 that, and it's 5HP. You're pulling a lot of HP with a feed like that. Right there could be a source of chatter.

                The depth of cut and spindle speed mean little without knowing diameter, workpiece and tool materials. It's all about SFM rates.

                Bright bar is quite common over here and is just polished mild steel without the scale.
                http://www.buau.com.au/english/files/BMS.pdf

                Dave

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                • #9
                  You just have crappy material.

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                  • #10
                    Originally posted by Davo J
                    Bright bar is quite common over here and is just polished mild steel without the scale.
                    http://www.buau.com.au/english/files/BMS.pdf

                    Dave
                    We just call it "TGP rod" (Turned, Ground and Polished rod), and the 1045 and 4140 are the most-commonly used steels. If you're going to bother, it might as well be decent quality steel.

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                    • #11
                      Just turn whatever machine that is operating with whatever cutter you are using on whatever material you are working on to the OFF position and the chatter should stop.
                      I hope this helps.

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                      • #12
                        Originally posted by Davo J
                        Bright bar is quite common over here and is just polished mild steel without the scale.
                        http://www.buau.com.au/english/files/BMS.pdf

                        Dave
                        Well it is just the finish really... Nothing to do with the grade, but yea most people associate bright steel with 1020 even though it refers to the finish only rather then mill scale finish.. (black)
                        Precision takes time.

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                        • #13
                          I would still like to know what kind of lathe he's using to take .080" on a side at 250 rpm with a feed of .046" per revolution.

                          That would be like cutting a 2 tpi thread. It must be one damn big lathe.
                          It's only ink and paper

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                          • #14
                            The OP has asked this before(check his prior posts) and didn't provide any more information, other than a very vague description of the lathe, after several requests.
                            I think he's using the metric system, so he's probably talking about a .031"(.8MM) DOC.

                            The OP is going to have to provide more information about the set-up such as; material diameter , how much is sticking out of the chuck, is the end supported, speed, and feed. Simply put, there are too many variables for an answer.
                            Harry

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                            • #15
                              Feed is one of the lower ones could be 0.0046 or 0.046 not sure as im not at the lathe at the moment. steel 1 inch dia

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