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DRO on a SB9

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  • DRO on a SB9

    I didn't want to drag a current thread on DROs OT so will start a new thread asking if any members here have fitted a DRO to their SB9 lathes? I'm particularly interested in installation photos of how they've handled the cross slide as that to me seems where I'll need to be the most creative. There was a recent article in MEW about removing the capacitive element off some Chinese calipers and sticking it to the saddle in the small gap between the saddle and the cross-slide. I thought it was a very clever solution to the problem, but clearly then only works with the DRO designed to use caliper scales.

    My lathe is an old imperial one, while I personally have migrated to metric, so being able to work directly in metric by way of DROs would be a massive bonus. If possible I'd also like to incorporate a spindle speed pickup and get direct readings of surface speed so I can get a little bit more "scientific" with my speeds. I was reminded yesterday that my "that looks about right" approach to speeds was about 2000% off when I actually measured the RPM, diameter, and plugged the appropriate numbers into the software

    Pete

  • #2
    Newall Microsyn is quite compact and highly rated, although also quite expensive.

    http://www.newall.com/upload/content...%20-%20C80.pdf

    http://www.practicalmachinist.com/vb...hucker-167438/

    Phil

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    • #3
      The biggest issue with a DRO on a Cross slide mounted in the "conventional" manner, i.e. alongside is as you say, how much space it takes-up. This potentially impacts tailstock positioning. This is especially true on smaller lathes where proportionally the width of the scale housing has more impact.

      One potential solution is to move the scale to an extension on the rear of the slide. The downside of the this would be a need to have space at the rear of the machine equivalent to the cross slide travel. This would get read of the issue of adding additional width to the Cross Slide itself.
      Hopefully the above description makes sense?

      Has anyone done it this way?, is it practical?

      Stuart

      Comment


      • #4
        Stuart, yes I've seen scales on many different model lathes mounted as you mention. I think it looks a little ugly myself. The problem is there seems to be only a limited number of positions to mount the scale. On the back it interferes with the tailstock, on the front with the chuck. On the back, as I mentioned above, a bit like an elongated wart. And out the front ... well what can I say! Mounting it in between the slides as I mentioned above really was a great solution, but I'm not sure what scales would be thin enough to do that. I have my slides apart at the moment actually, to clean out any cast iron the machine was swimming in after having to take a lot of a backplate. If I remember tomorrow I'll have a good look at just how much space is there and whether the "sandwich option" is a possibility.

        Pete

        Comment


        • #5
          Pete,
          Have you seen these?

          http://www.bwelectronics.co.uk/systems/334-335.html

          The work by a cable which can be buried inside the slide next to the screw so you loose nothing in travels or bulk.

          This photo I posted the other day of the chip guard on my CVA lathe also has one fitted.
          You can see the box at the top of the photo where the black cable tie holds the cable.



          Other than that nothing shows.
          .

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



          Comment


          • #6
            Look at page 11 in the first link in post #2.

            Also the GS30 scales on this link are quite small at 17mm by 20mm.

            http://www.dropros.com/DRO_PROS_Digi...dout_Scale.htm

            Phil

            Originally posted by PeteF
            Mounting it in between the slides as I mentioned above really was a great solution, but I'm not sure what scales would be thin enough to do that.
            Pete

            Comment


            • #7
              John I need the name of your optician.

              Phil

              Originally posted by John Stevenson
              You can see the box at the top of the photo where the black cable tie holds the cable.

              Comment


              • #8
                Originally posted by John Stevenson
                Pete,
                Have you seen these?

                The work by a cable which can be buried inside the slide next to the screw so you loose nothing in travels or bulk.
                Wow! No I hadn't seen, or even heard of that concept to be honest. That looks just about perfect for this application. How do you find the accuracy? I'm expecting it wouldn't be as accurate as a conventional linear scale?

                Pete

                Comment


                • #9
                  John isn't the accuracy a bit of concern for a lathe cross-slide.

                  http://www.bwelectronics.co.uk/systems/sysintro.html

                  Phil

                  Comment


                  • #10
                    Originally posted by philbur
                    John isn't the accuracy a bit of concern for a lathe cross-slide.

                    http://www.bwelectronics.co.uk/systems/sysintro.html

                    Phil
                    Yes it is because of the X 2 radius / diameter thing but short of glass scales with their attendant bulk, or the Newall ones with attendant costs, this will always rear it's head.

                    I have tried the cable system, the digital caliper system with remote readout and then the Shumatch but had to move to glass scales to get the accuracy and repeatability.

                    So really its a trade off against cost and bulk v accuracy and what it's going to be fitted to.
                    .

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



                    Comment


                    • #11
                      Hmmm, well maybe. But it gave me an idea. Could the cross slide scale be turned at 90 degrees so it hung down vertically off the back of the saddle, and the actual pickup driven by a SS wire cable looping around some pulleys and back to the cross slide? Hopefully that makes sense, I can picture it but that was probably a lousy description. Obviously the cable would introduce some errors, but it would almost certainly be more accurate than a rotary encoder.

                      Pete

                      Comment


                      • #12
                        Wow - some of the DRO options are worth more than the lathe!

                        I make due with the dial indicators for my SB9, and save the DRO for my clausing.

                        Comment


                        • #13
                          Go to the shooting star Website and see my Boxford which is a Southbend on steriods. Its about the third one down on the lathe list

                          http://www.star-techno.com/compat.htm

                          This is a super easy way to mount scales, that keeps them completely out of the way of the tail stock, and is very rigid.
                          You fasten a piece of precision ground stock on the top slide, square it up with an indicator, then pin it . You now have a square and plumb mounting surface for the scales -out of the way

                          Rich
                          I'll try to find bigger pics
                          Last edited by Rich Carlstedt; 03-06-2011, 01:10 PM.

                          Comment


                          • #14
                            Well, I found the pics so here they are

                            Since the top of the slide is parallel to the ways vertically it is only a matter of pinning the close end and swiveiling the plate until it is alligned L to R.
                            Then when the scales are mounted, just keep them parallel to the edge.The added benefit besides being out of the way, and easy mounting, is full protection of the scale by the plate above
                            Rich


                            Comment


                            • #15
                              Originally posted by PeteF
                              Hmmm, well maybe. But it gave me an idea. Could the cross slide scale be turned at 90 degrees so it hung down vertically off the back of the saddle, and the actual pickup driven by a SS wire cable looping around some pulleys and back to the cross slide? Hopefully that makes sense, I can picture it but that was probably a lousy description. Obviously the cable would introduce some errors, but it would almost certainly be more accurate than a rotary encoder.

                              Pete

                              Hi Pete

                              I made a cable operated lathe DRO:



                              http://madmodder.net/index.php?topic=781.0

                              Few people pass a positive comment on it which maybe becuase it is not expensive enough?


                              I have some improvement in mind. I have already managed to get the cross slide cable totally enclosed in the cross slide but one essential improvement, (which I have not done yet) is to wire up the calipers for external power and the batteries last such a short time I hardly ever get to use the DRO! Another improvement would be to replace all flexible cables with a metal tube, copper maybe, as with the scales mounted on the carriage as they are there is really no need for flexible cables.

                              Getting rid of the flexible cables would allow greater cable tension without the problem of the cable cutting the plastic linings of the flexible outers.

                              As it stands this is more accurate than the lathe scales and goes a long way towards avoiding gross errors. But I still need a micrometer to finish to an accurate diameter.
                              Last edited by The Artful Bodger; 03-06-2011, 03:58 PM.

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