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Adding a DRO to the lathe

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  • Adding a DRO to the lathe

    A little while ago I was looking at buying a VFD for a yet to be purchased wood lathe.

    In searching on Ebay I came across a VFD and 3ph motor for sale which also included a 2 axis DRO with 2 glass scales (as sold by Hafco).

    As I had plans to add a DRO to my metal lathe anyway, I placed a (very) late bid and was successful. I didn't fully understand all the capabilities of this (homemade) DRO and controller, it wasn't until I read the guy's website description properly that I got a feel for all this system can do.

    Now that Christmas is out of he way I decided to allocate a few days to installing the DRO part, not altogether sure whether I'll install the VFD and 3ph motor on the metal lathe as well at this stage. Might just keep that for when I eventually find the right wood lathe.
    Although it would be rather interesting to have fully integrated DRO and speed controller, time will tell which way I'll jump.

    For now I concentrated on installing the DRO and glass scales and associated brackets which came with the system. As this came off an almost identical 9x20 lathe most of the figuring out work was already done for me.

    First order of business was to remove the lathe from the bench it normally sits on so that I would have easy access to the back where most of this gear will go.

    I also took the opportunity to replace the existing speed control pot as it was a rather clunky component with no definite start and stop points. Having done that the occasional flashing of the speed readout also disappeared.

    Removed the splash guard and then the cross slide.

    This was to enable me to drill and tap a couple of mounting holes for the Y axis on the cross slide.

  • #2

    Trial mounting of bracket on cross slide

    Next the bracket for the X axis is installed

    A trial installation of the X axis support bracket

    Last edited by Steelmaster; 01-30-2010, 05:16 AM.


    • #3
      Then the support bar for the X axis glass scale (50x10mm aluminium)

      The glass scale is installed and the support bracket tested

      It needs to be perfectly aligned in parallel with the lathe bed, this done by mounting the dial indicator on the carriage and moving it end to end checking the deviation and making adjustments.


      • #4
        After installing the swarf guard on the X axis scale, the Y axis scale is installed

        It also has be checked for alignment to the cross slide with the dial indicator

        Next the DRO display box needs to be mounted


        • #5
          The package came with a rather large control box that holds all the electronics as well as the display. It uses a snazzy adjustable bracket. After some tiral and error I decided to mount it on the lathe itself, at the back of the headstock, using the existing bolt holes for the back cover.

          I used some 6mm aluminium plate I had to hand and drilled mounting holes matching the mounting on the lathe, then added mounting holes for the bracket.


          • #6

            Finally got ot mount the control box on the lathe, can't mis it!!

            All that remains now is:

            Some tidying up of the cabling

            Re-mounting the lathe on the bench, I will bring it more forward and raise it on 25mm blocks. I found that the way it was mounted was too close to the bench causing interference with the Norton gear box lever, as well as with the powerfeed lever.
            I also will need some more room behind the lathe because of the Y axis scale.

            Also need to either modify the existing splash guard or make a new one. For now I'll make a temporary guard over the motor until I work out the best way of doing this.
            Last edited by Steelmaster; 01-30-2010, 05:21 AM.


            • #7
              Nice documentation of your install. You will be glad you did the install, a DRO makes working much faster. Are you worried about damage to the scale hanging off the back?


              • #8
                When the DRO is bigger than the entire headstock of your lathe...
                You might want to consider getting a bigger lathe!

                Just kidding, redneck machinist humor.
                Nice install.



                • #9
                  Good Job and work-a-round.
                  Was your scale too tall for your carriage?
                  Here is how I did the cross slide on my Grizzly G4003G.


                  • #10
                    Great job. BTW, lathes have an X-axis (the cross feed) and a Z axis (the spindle). Y would be a move vertically perpendicular to the crossfeed and spindle axes. Thinking of it that way now will make any future transition to CNC a lot easier.
                    Stuart de Haro


                    • #11
                      Originally posted by Steelmaster
                      Now that Christmas is out of the way, I decided to allocate
                      a few days to installing the DRO part ...
                      Helpful write-up, nicely illustrated and, for me, timely.

                      I was just taking photos of existing DRO installations in a vocational
                      shop Thu evening to note how those had been undertaken.



                      • #12
                        Originally posted by gda
                        Nice documentation of your install.
                        You will be glad you did the install, a DRO makes working much faster.
                        Are you worried about damage to the scale hanging off the back?
                        No, it will be partially protected by the (modified) splash guard, will be posting pictures of that later.

                        Originally posted by Ron of Va
                        Good Job and work-a-round.
                        Was your scale too tall for your carriage?
                        Here is how I did the cross slide on my Grizzly G4003G.
                        The positioning of the scale was a design decision made by the original owner/designer of this setup. I was reluctant to deviate from his plan as I am very new to this. He gives reasons for his design decision on his website, see link in my first post.


                        • #13
                          Got the lathe back on the bench, took the opportunity to raise it on 25mm MDF blocks.

                          At the same time i moved the position of the lathe to the front of the cabinet top to give more room for the Y axis scale and modified splash guard (to come)

                          The extra 25mm makes a real difference to the working height which I had found to be a bit low, but more importantly it gives more room for the Norton gearbox lever and the X axis power feed lever, which hit the splash tray.
                          It also provides extra height for a bigger oven tray to be inserted under the lathe, assisting with removing swarf. I had a smaller and lower oven tray before but this one works a lot better

                          When I had all this in position I decided I didn't like the DRO sitting behind the headstock. First of all it obscured the tool board, not an insurmountable problem, but more importantly iw wasn't easy to read in the position.

                          After some experimentation I re-located it, using the supplied bracket, to the right of the tool board and angled slightly towards me.


                          • #14
                            I also took the opportunity to tidy the cabling using some rectangular conduit with removable top from Bunnies.

                            Used this setup for the first time yesterday and I was cery impressed the DRO. Very easy to turn to a given size and determine the length of a tenon on bushes etc.Hardly used the lathe dials at all, and a much reduced use of claipers and the digital indicator, so it was all worth the effort.

                            Also started on modifying the rear splash guard. Becuase of the 2 glass scales the standard is no longer suitable. Started by making to 2 cuts and bending the bottom part back to make room for the Y axis scale, but that wasn't successful, so decided to be a bit more drastic and cut the left side right off, giving me protection for the motor.

                            Was at the local 2nd hand dealer, a real treasure trove that one, and found a 1m sq sheet of 3mm PVC and will fashion the rest of the splash guard out of that. With a bit of heat it will be easier to bend than sheet metal without a brake.


                            • #15
                              One problem I was experiencing with the DRO was that the readout was rather dim, particularly as I have a fluoro mounted right above the lathe.

                              Queried the guy I bought it from, also the designer/builder, and he informed me that the firmware inside the DRO would have to be updated to change the brightness of the readout.

                              Delivered the DRO to him on Sunday morning and picked it up on my way home on Sunday afternoon. Brightness is now spot-on for these old eyes

                              Another job to be completed was the splash guard, it had to be modified to allow the Y-axis glass scale to travel along the X-axis.

                              I basically cut the splash guard in 2, see photo in previous post and used some 3mm PVC sheet to attach the 2 parts with a suitable slot to allow the Y-axis scale to travel along it. I also made the spash guard slightly longer to allow it to rest on the bench just outside the drip tray.

                              Close up of the slot and PVC sheet