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I have seen the light.

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  • I have seen the light.

    I just wanted to say that I have seen the light on 4 jaw chucks. Honestly, I have not used one since vo-tech in high school. I then thought they were a PITA and I don't really remember how well I actually got one dialed in.

    Well recently I got my lathe up an running at the house and need to use the 4 jaw to hold some square stock. I had to dial in a center hole in it and have since left it on for other jobs. I have found it very easy to dial it in to 3 jaw specs or better in little time. It does take less time to indicate a piece then it would to change the chuck out. I am not dialing in to tenths, but that wouldn't take a whole lot longer. I am not saying I will never put the 3 jaw back on, and that some of the jobs I have done wouldn't have been suited for the 3 jaw, but I am no longer afraid of the 4 jaw.

    What I have read others saying about the 4 jaw is certainly true. I am now a believer.

  • #2
    But.. now there is another bright light beckoning... soft jaws

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    • #3
      Originally posted by lakeside53 View Post
      But.. now there is another bright light beckoning... soft jaws
      That there is. I am lucky to have a 3 jaw with top jaws. I need to draw them up and once I get back to work they will be on the government project list.

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      • #4
        Have you tried this method of adjusting the four jaw.

        http://www.youtube.com/watch?v=2KMhx4DbyDg

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        • #5
          4 jaw is very nice. I think id only put my 3 jaw back in if I wanted to hold something thats hex very securely with maring it
          Play Brutal Nature, Black Moons free to play highly realistic voxel sandbox game.

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          • #6
            Now you got me thinking, were did I put my three jaw chucks? I know I have
            atlease three. Ill check for door stops.

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            • #7
              My lathe came with a very very nice 3 jaw which I took some amount of time dialing in and grinding. I had it to the point that it could repeat to .003-.005 runout. My 3 jaw is my most used chuck always! I have used my 4 jaw maybe twice.

              This is what makes me wonder when people say they like their 4 jaw more than their 3 jaws. I think to myself they must have a cheap or old worn out 3 jaw.
              Andy

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              • #8
                I run soft jaws in a 3 jaw virtually all the while, with that run out is good for 1 thou or thou and a half which covers 90% of normal work.

                They have just one step on them and when closed they can just enter a 25mm bore.
                This means that when sleeving a motor housing I can usually pick up in the rear seal track bore and bore out re sleeve and bore back to size in the time it takes me to swap to a 4 jaw and dial in a rough casting to get it running true in two planes and then have to do the job.

                In short I can do 2 jobs in the 3 jaw compared to 1 in the 4 jaw.
                4 or 5 jobs like this will easily buy you a brand new decent chuck to start with.

                Working smarter makes life a lot easier and more pleasurable.
                .

                Sir John , Earl of Bligeport & Sudspumpwater. MBE [ Motor Bike Engineer ] Nottingham England.



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                • #9
                  Please excuse my noob question...but what are the reasons a person uses soft jaws? If I had to guess, it sound like you machine to fit the lathe for greater accuracy?

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                  • #10
                    Yes.. you tension them and machine to the size you need... can't get much more accurate than that. Really useful for weird shapes or aspect ratios (like big flat disks). I use aluminum though, and don't trust them for other than light holding pressure. YMMV.
                    Last edited by lakeside53; 04-14-2013, 12:12 PM.

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                    • #11
                      Originally posted by vpt View Post
                      My lathe came with a very very nice 3 jaw which I took some amount of time dialing in and grinding. I had it to the point that it could repeat to .003-.005 runout. My 3 jaw is my most used chuck always! I have used my 4 jaw maybe twice.

                      This is what makes me wonder when people say they like their 4 jaw more than their 3 jaws. I think to myself they must have a cheap or old worn out 3 jaw.
                      For many applications 0.003-005 is not acceptable. I have set-tru 3 jaws chucks, but they take longer to dial in than a 4 jaw. I also have a "scroll PLUS individual adjust" 4 jaw.. that's really nice to have.

                      If I don't really care, or the operation is all "grab once, then cut", I use a 3 jaw (or whatever is on the lathe). If I really care.. and I need decent pressure - 4 jaw. Softjaws for really accurate "no adjust" or repeating work.
                      Last edited by lakeside53; 04-14-2013, 12:15 PM.

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                      • #12
                        In addition to the reasons given by Sir John and Lakeside, soft jaws
                        allow you to hold the work without marring or damaging
                        the finish where the work is gripped by the chuck jaws.

                        I cut it twice, and it's still too short!
                        Scott

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                        • #13
                          My soft jaws are aluminum shims.

                          Andy

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                          • #14
                            Originally posted by lakeside53 View Post
                            For many applications 0.003-005 is not acceptable.
                            Yeah, that's a lot of runout for some jobs. A decent 3-jaw will hold .002"-.003"; a set-tru type can be as good as .0005"--and, as has been said, can be a pain to set up. With practice it's quite easy to get a 4-jaw to run within .0005". In the end it's a matter of: A) Knowing how accurate a job has to be, and, B) Knowing which is the best tool for the job. There are lots of jobs where 3-jaw accuracy is all you need but there may be others where even a good collet setup won't be good enough. A fussy machinist will try to make everything as perfect as possible; an efficient machinist will only work to the level of accuracy needed for a particular job...
                            Keith
                            __________________________
                            Just one project too many--that's what finally got him...

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                            • #15
                              Originally posted by LKeithR View Post
                              Yeah, that's a lot of runout for some jobs. A decent 3-jaw will hold .002"-.003"; a set-tru type can be as good as .0005"--and, as has been said, can be a pain to set up. With practice it's quite easy to get a 4-jaw to run within .0005". In the end it's a matter of: A) Knowing how accurate a job has to be, and, B) Knowing which is the best tool for the job. There are lots of jobs where 3-jaw accuracy is all you need but there may be others where even a good collet setup won't be good enough. A fussy machinist will try to make everything as perfect as possible; an efficient machinist will only work to the level of accuracy needed for a particular job...

                              I did mention I do use the 4 jaw for those jobs that require it. But at least for me those jobs are very rare and even still I will loosen and re-tighten the 3 jaw while spinning the part multiple times and usually can get the part to spin true within a few tries doing this. Much easier than taking the 3 jaw off, pulling out and sticking the 4 jaw on and then adjust everything up.

                              But yes I totally agree there are those certain jobs that just need the 4 jaw.
                              Andy

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