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I'd like to build a carriage stop.

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  • #31
    For the record a micrometer stop and a feed stop are different tools for different purposes. My Nardini lathe comes from the factory with both. The micrometer stop as posted by Carl is not to keep one from crashing into the chuck. If you want to cut another 0.001 it is sure easier than a dial indicator. The feed stop on the Nardini is a trigger mechanism that is amazingly repeatable for disengaging the power feed. I still don't turn my back on it and I still jump ever time it trips and bonks the chip pan.

    This shows the bolt on the feed stop which is going to push the plunger that is sticking out from the side of the Apron.


    The stop lever shown in the engaged position.



    The stop lever shown in the disengaged position.


    The micrometer stop is shown here.

    Please excuse the poor photo but the Micrometer stop is substantial and stout and has a graduated dial for precision cut control.
    Byron Boucher
    Burnet, TX

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    • #32
      Hi guys:

      Been visiting outlaws for a few days and haven't seen your thoughtful responses. Thanks everyone.

      Just to clarify what I wanted:
      - I have no desire to leave the machine running and have the feed drop out before it hits the chuck. My post #9 was misleading that way.

      - All I want is a backup adjustable mechanical stop I can set and be confident that it will give me feedback if I mess up and go too far. I need to know that I will bump into it before I smash into the chuck. Willy and some others got it right.

      - In addition, I'd like to be able to face a piece, carefully measure it in the chuck, then be able to advance the carriage close to the final piece length(using the dial indicator) before measuring carefully again.

      Seems like there are lots of designs for these. You guys have provided some pictures, I can go from there.

      Thanks again.

      Mike
      Mike

      My Dad always said, "If you want people to do things for you on the farm, you have to buy a machine they can sit on that does most of the work."

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      • #33
        You should make a carriage stop that will also hold a dial indicator so you don't have to make two separate tools.

        As far as facing a piece, measuring it and taking a face cut again the standard method is to set the compound parallel to the ways, move the carriage so the cutter will take a face cut, tighten the carriage lock, then take the face cut with the crossfeed. Then measure the work and then use the compound to feed in how many thousandths you want to remove and take the cut with the crossfeed.

        If you start with the compound dial on "0" it is easy to know how much your removing.
        It's only ink and paper

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        • #34
          here is one I made quite some time ago. I'd make its base even wider (along the bed) now, but it serves well.





          1601

          Keep eye on ball.
          Hashim Khan

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          • #35
            In addition to a dial indicator, you might appreciate this tip on making fine cuts from South Bend's How to Run a Lathe "When the the compound is set at an angle of 84 degrees (84 - 16' to be exact) each graduation on the compound collar represents an angular movement of .001 in. and a cross-feed movement of .0001 in. or a reduction in diameter of .0002 in."

            I would assume that a corollary of this would be that setting the compound at six degrees would remove one thousandth off the face of your work with each complete turn of the compound screw.

            In regards to the earlier debate, South Bend offered a micrometer carriage stop for all of their lathes, so the original post was perfectly sensible, and a CNC lathe is no guarantee against crashes. You can program it to do all kinds of stupid things.

            I can't believe I have to use my first post in this forum to tell people to take a deep breath.

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            • #36
              While setting the compound to the 84 deg angle does produce an in feed of .0001" for every .001" of compound feed there are few lathes that can actually remove metal in those increments. I have tried and it does not always work. You have better luck with a file and emery cloth.

              With my current lathe I can take .001" per pass off of the work most the time. It depends on the type and quality of the metal many times.

              I will say that if your using a tool post grinder then setting the compound at 84 deg could be helpful.
              It's only ink and paper

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              • #37
                Where I find a bedstop most useful of all is when boring blind holes. My lathe has an adjustable overload dropout on long & cross feed, which I always thought was designed for running up against an adjustable bedstop. The bedstop is from the lathe's manufacturer, Harrison, and is pretty stout.

                I normally run with the feed disengage clutch backed all the way off, which still gives plenty of push to feed the tool. When the carriage contacts the stop, there's no obvious signs of anything getting overstressed, the feed just drops out. It makes boring to a set depth a breeze.

                However, I must admit, I very often drop the feed out a fraction before contact with the bedstop, and finish the last mm of travel by hand.

                Ian
                All of the gear, no idea...

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                • #38
                  Many lathes have a friction clutch on the carriage and crossfeed that is either flat plate or cone. The clutch on mine is a flat plate and is positioned to work on the carriage and crossfeed. Some have a ratchet type clutch like the feed on a BridgePort quill feed.

                  The repeated use of the clutch on the carriage/crossfeed causes wear on the plates. At some point they will need replacing. You have to decide if the continued use of slipping the clutch is worth the effort to repair the clutch.

                  The fact is you could get by with doing it for years or the entire time you own the lathe but at some point it will fail from over use of the clutch.
                  It's only ink and paper

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                  • #39
                    I was not recommending feeds of several tenths. At a setting of 84 degrees (or six degrees for facing) an entire turn of the compound screw would give a one thousandth cut, my compound has plenty of travel to make the average finish cut of .002-.005 inches with a high degree of control.

                    If that is too much precision then compound angles of 30 or 60 degrees could be used to give a ratio of 2:1.

                    I poached that tip from a South Bend publication because that I thought the mathematical use of the compound for fine feed control was useful. Using the compound gives a lot more control than the carriage feed wheel.

                    Any ratio can be calculated with basic trig. (Plenty of tutorials available on YouTube, much simpler than you think.) The travel of the cross slide is along the hypotoneuse of a triangle with sides of the ration you want to use. There Use of 14 or 76 degree angles will give a 4:1 ratio.

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                    • #40
                      The ONE BIGGEST trouble with angles for fine feed is that, at least in my case, the need for good precision often coincides with turning to a shoulder.

                      Naturally, when one angles the topslide for precise RADIAL travel, the whole notion of turning to a shoulder with a stop goes right out the window, because there is a larger axial travel of the cutter. You are continually changing the required position of the stop, making it useless.

                      In my opinion, everything you can actually USE for radial precision is attainable with a larger handle and dial on the crosslide. Larger dial to see the movement better, and larger handle to give better control.
                      1601

                      Keep eye on ball.
                      Hashim Khan

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                      • #41
                        Yup, the angle trick only good for fine control in one axis at a time. It will have the opposite effect on the other axis. (At 84 degrees there will be ten thousandths movement axially for each thousandth radially. Thanks for the reminder, it suck to find that out the hard way.

                        Motorradmike was talking about facing, where can be a useful trick.
                        Last edited by fciron; 01-05-2010, 12:08 PM.

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                        • #42
                          Oops, always refresh the browser before asking what happened to your post.

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                          • #43
                            fciron, I see your in the "BIG L", I'm not far from you. Glad to see another local machinist here.

                            The best use for angling the compound is when grinding. As to the compound, I keep it parallel to the ways and use it when taking clean up cuts on face cuts or to a shoulder.
                            It's only ink and paper

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                            • #44
                              I'm looking at making a stop, material choice??

                              I am new to this game and am looking to make a carriage stop for my Chipmaster. I am wondering about the best material to use that is going to give some durability but still be relatively easy to machine.

                              Thanks

                              Stuart

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                              • #45
                                Originally posted by Carld
                                fciron, I see your in the "BIG L", I'm not far from you. Glad to see another local machinist here.
                                Carld, I noticed you were down the road. I are not a machinist yet. I've got a little blacksmith shop mostly doing ornamental work.

                                Also, after all of my fussing I did the trig wrong. The slide moves on the hypotenuse, so the 30-60-90 triangle will not work. Maybe I will just go to your method instead.

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