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  • New DRO fitted

    Last week I got my new DRO from Lester Caine the UK agent for the Shumatech 350 DRO.
    See web page at http://www.shumatech.com

    I did a deal with Lester, in return for CNC machining a batch of cases he'd assemble a DRO for me. I though it was a good deal as if I'd have done it nothing would have worked. I'm not that hot with electronics, could be that my MIG can't get below 35 amps to do the chips may have something to do wth it.

    I want this for a lathe and as it's a three axis DRO Scott Shumate has allocated the 3rd axis either for an edge finder or a tacho.
    I talked Lester into setting this up so one Chinese scale worked two displays, both programable.
    This way I can use one on a front tool post and one on the rear without having to mess about calling tool offsets up.



    This shows the DRO box with the legends for X (F)ront and X(R)ear
    At the moment I don't have anything mounted to the long axis [ the Z ] but I hope to fit an encoder similar to a trav-a-dial to run this.
    The sender for the cross slide is just an 8" chinese scale.
    This has been mounted inside a milled out spar of alloy to protect it from damage and swarf.
    There is a glued on windscreen wiper blade rubber on the bottom to close the slot.



    Unlike a lot of mounting designs I have opted to keep the slider fixed to the rear of the saddle and move the scale. This way I have a secure fixed cable with no pulling.

    Running it today doing a few jobs and it seems to be keeping it's own as regards accuracy and repeatability but I only had jobbing work on.
    This lathe is about 4 to 5 years old now from new and the screws are still very good. Just comparing to the dials and it's always within 0.01 of a mm.

    John S.
    .

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




  • #2
    Slick set-up John. I like the trick using the third display for the back tool post.

    Comment


    • #3
      Thank you Forrest,

      Most people ask me why I need it and don't use the tool offsets provided but why mess around pressing buttons and swapping displays when yu have an extra one ?

      There is a section in the manual where you can fit the extra display to the top slide, program the set over angle in and the DRO will do the maths to keep everyting in line.
      Must admit I have not read that bit.

      Another alternative on a lathe is to use the tailstock but again in my case the rule on the tailstock is good enough for the work I do.

      I emailed Scott yesterday about stock as I now fancy a couple more of these and his page says he out of stock.
      Got a repy back to say that he'll be back to stock inside a month.

      I noticed his page lists built up boards for $110 with overlay, programmed up but no case.

      This is a cheap way to get a DRO
      $110 for the board $6.00 for a case, 2 or 3 scales from eBay for $20 - $50 depending on size and you have a near professional DRO that can outshine any of the hobby ones for 1/2 the price.

      The mill version which is probably the most popular can also do edge finding, bolt circles and work out the offset path.

      The case isn't hard to machine, you can do it with a dril and a file. The laugh is it doesn't even have to ook good, the holes can be all over as long as they clear the buttons. The overlay covers all your mistakes.

      Sorry if this sounds like an advert but I have no connection with Scott other than being a happy camper. Now he's doing premade boards it brings this project a lot closer to what people like me can cope with.

      John S.
      .

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



      Comment


      • #4
        I bought a cheap chinese Scale. I am planning on mounting it to the cross slide of the lathe, possibly with magnets, since I plan on using it for other things too. Problems with using magnets around a machine is it looks "furry" after a lil bit..

        They have a cable to connect the shumach to the scale, I'd rather go to a old pc. I still ain't had time to play with the communication of the two.

        Looks good.. 120, plus 40-60 per axis for scales is cheap. That is american money? I forget what money looks like lately.. I just see checks. *got married...

        David

        Comment


        • #5
          <font face="Verdana, Arial" size="2">Originally posted by ibewgypsie:
          I bought a cheap chinese Scale. I am planning on mounting it to the cross slide of the lathe, possibly with magnets, since I plan on using it for other things too. Problems with using magnets around a machine is it looks "furry" after a lil bit..

          Looks good.. 120, plus 40-60 per axis for scales is cheap. That is american money? I forget what money looks like lately.. I just see checks. *got married...

          David
          </font>
          IBEW,
          Why not use double sided tape, or Velcro or even blu-tak
          That way the bits won't stick to it.

          Yup true American $$$$ read the web site.

          You can even get a chrome case, plenty of glitter, gimme, gimee, - what was that ??? Gotta rush.

          John S.

          .

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



          Comment


          • #6
            Nice fitting John.

            Shows the real benefit of a taper gib rather than the normal side adjusted one that I'm working around!

            Charles

            Comment


            • #7
              Charles,
              That is a problem, using stand offs only reduces the tail stock travel.
              I think scale mounting on a cross slide is one of the hardest things with a DRO.

              I was looking at my CVA lathe today.
              At the moment it has a BW Electronics wire on an encoder drum type but it's not reliable enough. Easy to fit as the wire cable runs along side the leadscrew.
              The problem to fitting an 8" scale to this lathe is the cross slide is a low profle jobbie, nowhere near as high as the TOS in the picture.
              Added to this is the guard at the rear covering the taper turning attachment rises up about 1/2" which reduces the hight even further.
              I'll have to study this a bit more.

              Ran the lathe today doing three electric motors for repair. All had bad rotor journals that required welding and turning back to size and out of the three motors, I had to sleeve 4 end housings [ 2 on one motor ]

              Started with the housings first, put the boring tool on the quick change tool post and took a cut, measured it and set the DRO to this reading.
              Took another cut and checked it, slightly out by 0.08mm so reset it again. Another cut, checked it and it was reading OK.
              Bored out and pressed repair sleeve in then took two cuts to get close to the finished bearing size of 100mm.
              Rechecked and still bang on. Got to 0.03 and stopped checked and it was 0.03, polished to fit as usual.
              Did the other housing the same checking all the while but never had to reset the reading.

              Did the same with the journals and a normal knife tool and again it took two inital settings to get the readings to match and then after that no problem.

              I'm not someone who because thay have bought or got something then it has to be the best thing since sliced bread. I've bought my share of lemons , I've even made my share , That co-ax indicator I made the other day was just over a night wasted as it's too big / slow to use quickly. But I am impressed with this DRO unit.

              I had previously bought three BW units but as soon as I can get new boards off Scott then these will go on eBay. The laught is they will fetch more than a board, case and scale!

              John S.
              .

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



              Comment


              • #8
                I'm looking for one that will do my 8 ft planer table in mill mode that will disengage quickly when I shift it into planer mode.

                I suppose I could use a block and tackle and a big spring to multiply the 32" one to work on 96" but something tells me there's something wrong with this trick.

                Comment


                • #9
                  Snap balls to mount? I saw some in the bottom of my junk bucket.. You know like on a throttle of a antique car?

                  I wonder how great them scales are..

                  My mitutoyo digimatic caliper has not let me down yet.. I kinda feel bad that it is not American but.

                  They make a desk model of that? 232 input.. I copy some measurements off into my cad program sometimes.. *not bobcad..

                  David

                  Comment


                  • #10
                    Forrest,
                    What sort of accuracy are you looking for?

                    I have yet to do the Z axis on the lathe, mine is 40" or an imperial metre
                    Scales this long, even Chinese are expensive here and hard to get, also I don't need a great accuracy on the bed. At the moment I use the handwheel dial or a rule.
                    This is plenty good enough for 99.9% of my work.

                    What I propose to do is to get a fine straight knurling wheel, mount it in a holder with two bushes, one either side and fasten this to the apron so the wheel runs on the back side of the machined bed in a position that's not used.
                    By removing mounting shims and keep runnng up and down the bed it will force this wheel to cut a rack, similar to a Trav-a-Dial.
                    I then aim to swop the bushes for bearings, [ didn't want to start with the bearings in case they got brinneled ] and then mount a shaft encoder on the end of the knurl shaft with a small coupling.
                    The DRO already has a convertor fitted to read this instead of Chinese scales on the Z and it can be programmed to read whatever pulses.
                    It's just a matter of traveling a set distance, taking a reading and juggling the input value to get close.
                    This may have to wait a while as bloody customers keep getting in the way.

                    Perhaps you could do similar but have yours on a hinged mounting?

                    John S.
                    .

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



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