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  • 4 jaw chuck

    How long should it take a machinest versus hobbiest to clock up something in a 4 jaw.?

  • #2
    Take a look! Not long if one is doing it with some regularity.

    https://www.youtube.com/watch?v=0IStp69jcJU&t=743s

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    • #3
      Originally posted by RMinMN View Post
      Take a look! Not long if one is doing it with some regularity.
      Neither of those guys would be considered hobbyists in my book. Both are paid machinists and use a 4-jaw daily. The key is knowing the basics and practice--Tighten the highs and loosen the lows.

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      • #4
        2 minutes to get within 1/2 a thou. for short parts.
        Longer parts that require tapping in, maybe 4 minutes.

        -D
        DZER

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        • #5
          Originally posted by Doozer View Post
          2 minutes to get within 1/2 a thou. for short parts.
          Longer parts that require tapping in, maybe 4 minutes.

          -D
          Thats what I'd guess. Shouldn't take to long after you've done it 4-5 times.
          Andy

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          • #6
            My personal record was 5 seconds, I stuffed the bar in tightened it and bingo, the bugger was spot on, it has happened once in 40 years, the longest was 2 days, I’m not joking, it was an irregular thing in a big chuck so not home shop, it was a valve body at about 200 kg btw
            Average is about 4 or 5 mins tinkering and tapping, tip I just made a couple of copper protectors, make the captive ones that don’t fall off all the time, bloody annoying
            Like all things the more you do it the better you get (thinking welding, mines really good, after about a week!, goes to **** if the welder is a dust shelf)
            A really good clock is vital, a good starett will look after you, you can do it with a Chinese alarm clock but it’s painful
            Mark

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            • #7
              I'm definitely a hobbiest but as has been said on short parts I'm down to a minute or two and at this point I don't have to relearn every time I do it.

              1) Dedicated QCTP indicator holder on center(my dial indicators are cheapies but all work very well. I have a good DTI).
              2) Remember to tighten highs and Loosen Lows (Lows spin the needle Left (CCW)).
              3) Get under 0.100" by eye so you don't have the needle spinning around multiple times.
              4) Get the part in just tight enough to not shift around when rotating the chuck, but not more. Loosen the lows first until you're close (within 0.010") otherwise you can't make much progress when you try to tighten. I made two keys but don't tend to use both.
              Last edited by JCByrd24; 08-17-2018, 02:13 PM.

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              • #8
                Originally posted by Doozer View Post
                2 minutes to get within 1/2 a thou. for short parts.
                Longer parts that require tapping in, maybe 4 minutes.

                -D
                +1.
                Wot he said.
                Sometimes quicker, occasionally slower.

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                • #9
                  If using the 4 jaw all and is about same less that 4 min.
                  If you changing from inside to outside jaws add 10 min on small lathes up to 13"
                  Very large lathes up to 1/2 to 1 hour

                  Dave


                  Originally posted by plunger View Post
                  How long should it take a machinest versus hobbiest to clock up something in a 4 jaw.?

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                  • #10
                    I use the 4jaw more than the 3jaw set-true. I laugh when some people boast about have expensive 3 or 6 jaw set-true chucks, cause you adjust them the same way. Only jaw pressure is different. I do a fair amount of barrel work, so I am doing the same thing on both ends. Still, I can get both ends down to a tho' in a few minutes, then tweaking takes a bit longer. It's not a time issue with me, it's the accuracy.

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                    • #11
                      When I use my 4 jaw on my T&C grinder I'm usually shooting for a tenth or less because if I have to grind it's for precision. So........ sometimes it's taken me all of 5 min.
                      I always start with putting a post or something up against the part it to get close visually, then go to a .001 dial and then my tenths dial.

                      JL................

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                      • #12
                        Originally posted by CCWKen View Post
                        Neither of those guys would be considered hobbyists in my book. Both are paid machinists and use a 4-jaw daily. The key is knowing the basics and practice--Tighten the highs and loosen the lows.
                        I actually watch both of those guys videos on using a 4-jaw to learn how. The first couple times I did it on rough parts it probably took me ten minutes or more. On something like TGP round It goes fast enough I don't sweat it anymore. I almost felt like they struggled more in their video competition due to the time pressure than I have seen them in their regular videos. One of the things both of those guys taught me was to decide what my acceptable tolerance was rather than to try to seek out a dead still needle on a tenths indicator. Under half thou for most things is my goal, which is what Adam Booth achieved in their competition video. I've done a few things I wanted closer like when blending in turnings from opposite directions after rotating the part. I just take my time and zone in on what I am doing. It goes pretty quick. I think for a hobbyist who has done it a more than a couple times 5 minutes is not unreasonable. Ten minutes is not at all unreasonable for somebody who knows the steps, but hasn't much practice, but to be honest the time isn't really important. Take your time, and just work towards your acceptable tolerance. It will get done much faster than if you stress over how long it takes. Just don't worry about it. Its your project and setting up the job right is just something that needs to be done. If I was paying you by the hour and you claimed to be an experienced machinist I might begrudge you taking half an hour, but for your own project take all the time you need. Your are the one who has to live with the part you make.
                        *** I always wanted a welding stinger that looked like the north end of a south bound chicken. Often my welds look like somebody pointed the wrong end of a chicken at the joint and squeezed until something came out. Might as well look the part.

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                        • #13
                          I seldom use a 4 jaw and get frustrated using one. I forget. It takes me about five minutes if I havent done it for a couple months. Is there a proper procedure. ?

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                          • #14
                            Originally posted by plunger View Post
                            I seldom use a 4 jaw and get frustrated using one. I forget. It takes me about five minutes if I havent done it for a couple months. Is there a proper procedure. ?
                            For me measuring the part with a scale and then roughing the jaws to that relative to a center in the tail stock really helps a lot. My biggest problem is making sure in my head I am reading the indicator in the right direction. After that it goes pretty quick.
                            *** I always wanted a welding stinger that looked like the north end of a south bound chicken. Often my welds look like somebody pointed the wrong end of a chicken at the joint and squeezed until something came out. Might as well look the part.

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                            • #15
                              I made a knob key for adjusting the 4 jaw that I use on my grinder. It saves a lot of time because the standard key is too big to get around the chuck. Either the workhead was in the way, the table bottom or the quill. The knob solved the issue as I can get to all four jaw screws without any interference. Then I give them the final snug with the key checking the indicator for any movement. You can get to a point where you start over tightening the jaws to get dial readings and that's probably springing the chuck body.
                              I guess that's why you don't see 4 jaw chucks with fine jaw threads, it would be too easy to over tighten, but it would make fine adjustments easier.

                              JL.................



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