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10" 4 jaw chuck almost 4" center hole looks good to me

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  • #16
    My Victor 10 inch 3 jaw at 25 years old was pretty good, usually clamp round at 2 to 5 thou runout.
    If there is 5 and you turn and reclamp it usually gets better.
    I did regrind the inside of the jaws at one point, but it's always been a good chuck.
    The 5 inch Pratt on my S Bend is pretty good too.

    Regarding the 3jaw not accurate BS,
    I think a lot of this comes from really low quality chucks that are sloppy or worn or sellers putting a tired chuck on a machine to sell it.

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    • #17
      Originally posted by 754 View Post
      Regarding the 3jaw not accurate BS,
      I think a lot of this comes from really low quality chucks that are sloppy or worn or sellers putting a tired chuck on a machine to sell it.
      Personally, I suspect that the "low quality" idea comes from expectations. If I have a lathe spindle that is true to .0002 and if I can cut a cylinder that is accurate to .001 over 5 inches, I'd sort of expect the chuck that comes with it to be in the same accuracy range. At least I had that expectation when I got my first lathe. I was appalled it the variable TIR that the little 3 jaw chuck had.

      Now I don't expect as much any more. That does not mean that it's junk, just that the design does not lend itself to high accuracy.
      At the end of the project, there is a profound difference between spare parts and left over parts.

      Location: SF East Bay.

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      • #18
        Originally posted by danlb View Post
        Does anyone know why they don't make master + top jaws for smaller scroll chucks like the ubiquitous 3 inch chuck that comes with the small lathes?

        Dan
        That's a good question,I have wondered the same and making my own set is on the list.It to me would be a no-brainer given how much more capability two piece jaws add for the larger chucks.Given all the odd setups and accuracy issues HSMer's run into a small 3 or 4" three jaw with two piece jaws would really be handy.

        I plan on taking the ouside jaws for the 3-jaw on my 9x20 lathe and annealing them in the heatreat furnace.Milling the tops off, keying and drilling and tapping for top jaws,then re-heat treating them.I think there is enough meat there for 1/4-20 threads in the "master jaws".
        I just need one more tool,just one!

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        • #19
          Originally posted by Mcgyver View Post
          . My comments come from my shop paradigm, where the jaws are solid.
          You should indulge yourself in two-piece jaw bliss.Heck I think even 4-jaw chucks should have two piece jaws
          I just need one more tool,just one!

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          • #20
            Originally posted by wierdscience View Post
            Read it again,the ebay listing says -Independent-
            The photo said self centering and the looks like too

            Try shars.com they good prices and purchase a 8" a few years ago works great

            Dave

            Sent from my SAMSUNG-SM-J320A using Tapatalk

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            • #21
              Originally posted by smithdoor View Post
              The photo said self centering and the looks like too

              Try shars.com they good prices and purchase a 8" a few years ago works great

              Dave

              Sent from my SAMSUNG-SM-J320A using Tapatalk
              The description is quite clear.

              Combine the advantages of a scroll chuck with those of an independent chuck • Each jaw may be adjusted individually with an independent operating screw • After the desired eccentric setting has been made, all jaws can then be opened and closed simultaneously with the use of a scroll and pinion
              Location: Saskatoon, Saskatchewan, Canada

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              • #22
                Originally posted by Arcane View Post
                The description is quite clear.
                Sigh....
                One of you is talking about the EBAY listing (standard scroll) and one is discussing the AJAX TOOL listing, which is a combination of scroll and independent jaws.

                Just hoping to clear it up without hard feelings.

                Dan
                At the end of the project, there is a profound difference between spare parts and left over parts.

                Location: SF East Bay.

                Comment


                • #23
                  Originally posted by danlb View Post
                  Sigh....
                  One of you is talking about the EBAY listing (standard scroll) and one is discussing the AJAX TOOL listing, which is a combination of scroll and independent jaws.

                  Just hoping to clear it up without hard feelings.

                  Dan

                  Opps! You're quite right! My apologies to smithdoor.

                  Boy, I'm sure glad I didn't say anything even more embarrassing!
                  Location: Saskatoon, Saskatchewan, Canada

                  Comment


                  • #24
                    Originally posted by 754 View Post
                    My Victor 10 inch 3 jaw at 25 years old was pretty good, usually clamp round at 2 to 5 thou runout.
                    If there is 5 and you turn and reclamp it usually gets better.
                    I did regrind the inside of the jaws at one point, but it's always been a good chuck.
                    The 5 inch Pratt on my S Bend is pretty good too.

                    Regarding the 3jaw not accurate BS,
                    .
                    If you think its BS, and your chucks are to 2-5 thou out, you never do work that requires better than that?
                    in Toronto Ontario - where are you?

                    Comment


                    • #25
                      Originally posted by wierdscience View Post
                      Edit: Yes,of course you want to complete the part in one chucking whever possible,3/4/6 jaw or not,that's just common sense.

                      Repeatbility-Not necessiarily,on a quality 3-jaw the final step in manufacturing is to chuck a lash ring and then do the final grind on the jaw faces.When that is done,the pinion used to clamp the lash ring is marked.That pinion is known as the master pinion.It is the only one of the three that will produce repeatable runout because of the way a scroll chuck is designed.On a Bison 3-jaw the master pinion is marked usually with a -0- stamped in the chuck body right next to the master pinion.
                      On Bison chucks anyway,the jaws and slots are numbered 1-3 and so long as you always keep the jaws in their mating slots and use the master pinion the chuck will repeat.Some people insist on using all three pinions to tighten a chuck,that's fine,whatever storied talisman floats your boat,just so long as the last pinion tightened is the master.
                      This holds true throughout the whole use/truing of the jaw faces and or soft jaws.Always use the master pinion when taking out the lash before machining/grinding.
                      I do not think any of my chucks have more than one pinion, so no issues finding it..... Using that makes everything better, but it still is not super accurate unless you have set the adjust tru, or are using bored soft jaws. And the scroll can screw things up if it shifts around at all, so scroll center bearing wear is an issue. Have shimmed a couple chucks to fix it, with good results.
                      2730

                      Keep eye on ball.
                      Hashim Khan

                      Everything not impossible is compulsory

                      Comment


                      • #26
                        Originally posted by Mcgyver View Post
                        If you think its BS, and your chucks are to 2-5 thou out, you never do work that requires better than that?
                        Just to throw my two cents in... A chuck that is .005 out usually just holds the work off center. That can be worked around. Shims can center it. Grinding can help with the bellmouth condition. Soft jaws correct a host of flaw

                        If jaws are worn or otherwise damaged/worn, then that's a different story but it can still be worked around.


                        Dan
                        At the end of the project, there is a profound difference between spare parts and left over parts.

                        Location: SF East Bay.

                        Comment


                        • #27
                          Originally posted by danlb View Post
                          Just to throw my two cents in... A chuck that is .005 out usually just holds the work off center. That can be worked around. Shims can center it. Grinding can help with the bellmouth condition. Soft jaws correct a host of flaw

                          If jaws are worn or otherwise damaged/worn, then that's a different story but it can still be worked around.


                          Dan
                          yeah you could do that stuff, but reality is when you need two surface concentric, really concentric like to .0002" as sometimes happens like the spindle housing I just did, you do things in one setting or you use the four jaw for the second ops. That's why 4 jaw accuracy matters more to me than 3 jaw.
                          Last edited by Mcgyver; 07-22-2018, 06:43 PM.
                          in Toronto Ontario - where are you?

                          Comment


                          • #28
                            For a lot of work it does not matter much. (The lathe has been not wired up the last year and a half)
                            I think at times I used a 1 1/2 or 2 thou shim under a certain jaw.nand it would bringbitbunder 2 thou.
                            The point I am making is it has always been a very good chuck 95 percent of the time, and never was an issue for 90 percent of the work.

                            But what I keep reading often on here, is that folks have 3 jaws, that cant easily clamp work at 3 thou TIR or under, and then rely on a 4 jaw for that kind if work.. that us not the case for my lathe..
                            And I used it every week for 28 years and the chuck was always very good.
                            And it came with the lathe, not like I had to buck up out of my wallet to try to get something better, to improve the situation.
                            Not sure if that clears up what I meant.

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                            • #29
                              What I do use a lot..
                              I have a 6 inch 4 jaw threaded to fit south bend spindle I think.
                              I made a straight adaptor about 5 inches long , plus the chuck threads and register and I mounted the 4 jaw on that.
                              I have a 16 in lathe with 10 inch 3 jaw.
                              My 14 inch 4 jaw weighs about 90 lbs and I have a Camlock spindle.
                              So many, many times for small 4 jaw works I clamp the 6inch 4 jaw with the arbor I made into the 3 jaw. great for pieces 4 inches square or less.. saves the cleaning and mounting of the heavy 4 jaw.

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                              • #30
                                All the discussion brings up relevant and important points.

                                I am leaning toward trying the big hole chuck....as an additional.... four jaw for that lathe ,which is a 16" leblond dual drive , the center hole is 1.6".......Right now I have 3 four jaw chucks that fit that machine........a heavy duty 10" ....an 8 inch.... and a 4" and one 8 jaw I made , , a front and back set of 4 radial bolts , in tapped holes in a very heavy wall tube, allowing dead on center line workpiece adjustment with lathe centerline........and a There is a 6" 4 jaw SELF CENTERING PLUS independent adj on each jaw here too, the yard sale sticker price $8 still on it, havent mounted it to a backing plate yet.

                                The current discussion kind of stimulated my mind, and since the immediate reason for buying it is to gain the use of the large center pocket,behind the jaws I think I will space it out about 4 inches off the mounting plate, probably using some 8" pipe i have ,allowing it too hold aprox 9" of stock to the left of the jaw face.
                                Need it very often ? no.....need it somtime ? for sure

                                And for the times the jaws are not "streight" enough or whatever its called , it will be easy to drill and tap 4 holes in the pipe for a "spyder" or whatever its called , effectively turning it into an 8 jaw chuck

                                Dave Lawrence
                                Hummmm
                                Last edited by lalatheman; 07-23-2018, 10:29 AM.

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