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Re: [SherlineCNC] Difficulty of using a CNC Mill/Lathe?

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  • Jerry Jankura
    Greg Procter wrote: Hi, Greg - Let me share some thoughts on your points.... ... That s a good way to look at it. The machine, by itself, is not very useful.
    Message 1 of 11 , Sep 5, 2007
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      Greg Procter wrote:

      Hi, Greg - Let me share some thoughts on your points....
      > CNC is IMO a way to _improve_ the things I make and also provide _extra_
      > possibilities.
      >
      That's a good way to look at it. The machine, by itself, is not very
      useful. It's only when you couple the machine's capabilities with your
      ideas that you can begin to produce something useful.
      > Designing parts is easy, the hard bit is designing useful parts that can
      > be made with the equipment you have.
      >
      I think that some of the issues arise because you're trying to learn
      several different fields at one time. It's one thing to "know what you
      want" and another thing to put it on paper (or on a display) in a manner
      that you can convey to another human or to a machine what you want. And
      then, there are the issues of tolerances and build up. Fortunately, most
      of us are not in a production "make a million" environment and can hand
      fit everything that we make.
      > I've been bumbling with CAD for the last 6-8 weeks, (before that I
      > always designed on paper) and I think I'm coming to terms with the
      > basics.
      >
      Isn't it fun?!? Actually, selecting a CAD program is almost like getting
      married. You've got to choose carefully because, once you've invested
      quite a bit of time learning, you really don't want to move on to another.
      > G-code is a bit like computer programing - actually it _is_ computer
      > programing. Sherline provides another program which converts CAD to
      > G-code. However, CNC operators seem to understand G-code so I'll guess
      > that conversion programs either aren't perfect or there's still bits
      > like feed rates that need manual tweeking 8-)
      > Everyone here seems to use programs other than the Sherline provided
      > programs and I've still to find out why. I'm sure I'm going to find out
      > the hard way! :)
      >
      One reason is that Sherline was rather late to the gate with their
      factory-built CNC equipment. By the time they integrated a computer and
      G-Code interpreter to the motors, coupling kits, and machines that they
      sell, a lot of us have already built our own motor drives and integrated
      a G-Code interpreter to it. I got into CNC probably around 2002. When I
      did, I had no choice but to find a motor drive and software to
      compliment the equipment I purchased from Sherline. Even now, Sherline
      does not seem to be keeping current with the software that they DO
      offer. The last I'd heard, they're still including the same version of
      EMC that they started with, while EMC has undergone several revisions.
      I'm guessing that - although Sherline's turn-key systems have been
      around for a few years now - they still comprise a small minority of the
      user community.

      Personally, I moved from a DOS based program - TurboCNC - to the Linux
      based EMC around the first of the year. At that time, I had to decide
      whether to go with Sherline's offering (which isn't really supported or
      enhanced) or to go with the "generic" version of EMC which is supported.
      I chose the generic. I first ran with Puppy Linux as the base operating
      system, but then moved over to the Ubuntu version as soon as I had a
      computer that had enough memory so that I could install it. EMC version
      2.x running under Ubuntu Linux (with real time extensions) seems to be
      the version that has most of the support. BTW, it works quite well with
      Sherline's machines.

      Other folks are married to Windows based systems and don't want to have
      two different operating systems on their computers, or don't want to
      take the time required to learn enough of Linux to effectively use EMC,
      so they usually select Art Fenerty's Mach or Master CNC G-Code
      interpreters.

      I hope this gives you some understanding why many of us made the choices
      we did. At the time, we simply had no choice. Now that we've got working
      systems, there's no need to retrofit.
      > You definitely need to be able to operate or understand a manual lathe
      > or milling machine before moving to CNC.
      >
      Although that certainly helps, I'm not sure that I'd agree with you. You
      can break tools, etc. just as easily with CNC as you can with a manually
      run machine. I know that I did not have a good grounding in manually
      running either the mill or the lathe when I added CNC to the mill. It's
      definitely been a learning experience.

      -- Jerry Jankura
      So many toys.... So little time....
    • Greg Procter
      ... I m full of ideas - sometimes I wish I had less of them! ... I could make a million??? I guess I d have to be interested in money as an end in itself -
      Message 2 of 11 , Sep 6, 2007
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        Jerry Jankura wrote:
        >
        > Greg Procter wrote:
        >
        > Hi, Greg - Let me share some thoughts on your points....
        > > CNC is IMO a way to _improve_ the things I make and also provide _extra_
        > > possibilities.
        > >
        > That's a good way to look at it. The machine, by itself, is not very
        > useful. It's only when you couple the machine's capabilities with your
        > ideas that you can begin to produce something useful.

        I'm full of ideas - sometimes I wish I had less of them!

        > > Designing parts is easy, the hard bit is designing useful parts that can
        > > be made with the equipment you have.
        > >
        > I think that some of the issues arise because you're trying to learn
        > several different fields at one time. It's one thing to "know what you
        > want" and another thing to put it on paper (or on a display) in a manner
        > that you can convey to another human or to a machine what you want. And
        > then, there are the issues of tolerances and build up. Fortunately, most
        > of us are not in a production "make a million" environment and can hand
        > fit everything that we make.

        I could make a million??? I guess I'd have to be interested in money as
        an end in itself - I've got too many ideas for that to ever happen -
        meanwhile I'll just have to cope with being happy with what I'm doing.
        =8^)

        > > I've been bumbling with CAD for the last 6-8 weeks, (before that I
        > > always designed on paper) and I think I'm coming to terms with the
        > > basics.
        > >
        > Isn't it fun?!?

        Err, unfortunately I'm discovering the additional flexibility of CAD
        over manual draughting - it's much easier to set all my ideas down on
        screen/paper.

        > Actually, selecting a CAD program is almost like getting
        > married. You've got to choose carefully because, once you've invested
        > quite a bit of time learning, you really don't want to move on to another.

        I've got Autocad LT stashed in a carton somewhere until I get sorted
        with the new house and workshop - meanwhile I'm muddling along with
        shareware off the internet.

        > > G-code is a bit like computer programing - actually it _is_ computer
        > > programing. Sherline provides another program which converts CAD to
        > > G-code. However, CNC operators seem to understand G-code so I'll guess
        > > that conversion programs either aren't perfect or there's still bits
        > > like feed rates that need manual tweeking 8-)
        > > Everyone here seems to use programs other than the Sherline provided
        > > programs and I've still to find out why. I'm sure I'm going to find out
        > > the hard way! :)
        > >
        > One reason is that Sherline was rather late to the gate with their
        > factory-built CNC equipment. By the time they integrated a computer and
        > G-Code interpreter to the motors, coupling kits, and machines that they
        > sell, a lot of us have already built our own motor drives and integrated
        > a G-Code interpreter to it. I got into CNC probably around 2002. When I
        > did, I had no choice but to find a motor drive and software to
        > compliment the equipment I purchased from Sherline. Even now, Sherline
        > does not seem to be keeping current with the software that they DO
        > offer. The last I'd heard, they're still including the same version of
        > EMC that they started with, while EMC has undergone several revisions.
        > I'm guessing that - although Sherline's turn-key systems have been
        > around for a few years now - they still comprise a small minority of the
        > user community.
        >
        > Personally, I moved from a DOS based program - TurboCNC - to the Linux
        > based EMC around the first of the year. At that time, I had to decide
        > whether to go with Sherline's offering (which isn't really supported or
        > enhanced) or to go with the "generic" version of EMC which is supported.
        > I chose the generic. I first ran with Puppy Linux as the base operating
        > system, but then moved over to the Ubuntu version as soon as I had a
        > computer that had enough memory so that I could install it. EMC version
        > 2.x running under Ubuntu Linux (with real time extensions) seems to be
        > the version that has most of the support. BTW, it works quite well with
        > Sherline's machines.
        >
        > Other folks are married to Windows based systems and don't want to have
        > two different operating systems on their computers, or don't want to
        > take the time required to learn enough of Linux to effectively use EMC,
        > so they usually select Art Fenerty's Mach or Master CNC G-Code
        > interpreters.
        >
        > I hope this gives you some understanding why many of us made the choices
        > we did. At the time, we simply had no choice. Now that we've got working
        > systems, there's no need to retrofit.

        Yes, that's all useful - I thought I might be heading for some major
        dead-end with Sherlines programs.

        > > You definitely need to be able to operate or understand a manual lathe
        > > or milling machine before moving to CNC.
        > >
        > Although that certainly helps, I'm not sure that I'd agree with you. You
        > can break tools, etc. just as easily with CNC as you can with a manually
        > run machine. I know that I did not have a good grounding in manually
        > running either the mill or the lathe when I added CNC to the mill. It's
        > definitely been a learning experience.

        I was thinking in terms of learning _three_ major different things at
        once.

        >
        > -- Jerry Jankura
        > So many toys.... So little time....
        >

        I've applied for a second lifetime - still haven't heard back from the
        suppliers!

        Regards,
        Greg.P.
      • Yahoo
        Here s my experience: I bought a Sherline Mill and Lathe in 1998 to make parts for a prototype automatic pool cleaner I wanted to build. I planned to use
        Message 3 of 11 , Sep 6, 2007
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          Here's my experience:

          I bought a Sherline Mill and Lathe in 1998 to make parts for a prototype
          automatic pool cleaner I wanted to build. I planned to use mainly soft
          materials, plastic, aluminum, brass. I did finish the prototype but boy was
          it ever time-consuming. I was in my garage twiddling those little crank
          handles for weeks. After I finished the initial project I still had the
          machines with lots of accessories. I started wondering if it was possible to
          automate the process and found lots of stuff online. Sherline didn't have
          their EMC retrofit yet, but did have the stepper motor adapters. I bought a
          cheap driver board and hooked it all up. The steppers were really gutless
          because the Stepper3 driver board didn't use PWM current regulation (live
          and learn!) It looked like everything on the market was really cheesy or
          really expensive, so I decided to design my own electronics and see if there
          was a mid-range market. As I learned more about CNC I discovered there were
          significant limitations using the Sherline hardware with CNC retrofit. It
          was not designed for CNC and really is not very well suited for it. It lacks
          the necessary rigidity for heavy cutting or hard materials, and the working
          envelope is quite small. Because of the way the backlash adjustment is made,
          when the X-Y lead screws begin to wear you cannot reduce the backlash
          without binding at the extreme ends of travel. The lead nuts tend to come
          loose easily, and are difficult to tighten or replace. The same is true of
          the slide ways and gibs. There is no way to adjust the backlash on the Z
          axis. The spindle motor tends to overheat if run for long periods of time,
          which is common in CNC applications. I got better drivers and bigger stepper
          motors but found that just made it easier to break things by accident or
          wrench the machine out of alignment. Many times I wanted to use the machine
          manually for some quick job, but the CNC setup made that difficult or
          impossible. I debated building a manual control interface for cases like
          that, but I think it might be more practical just to get another machine.
          CNC is good for highly repetitive tasks or cutting highly complex shapes or
          jobs that require many light cutting passes. The machines require quite a
          bit of mechanical maintenance and careful adjustment, so unless you have a
          lot of repetitive work or a lot of very complex machining to do, it may not
          be worth the hassle. It can be fun to tinker with if you enjoy that for its
          own sake, but if you see it as a means to an end it can easily become more
          of an obstacle than a solution. Just remember that you need more precision
          (less backlash and sideplay) for CNC than for manual machining. I would
          suggest learning to machine manually first, then learn how G-Code works
          (Google RS274-NGC), then learn how motion control hardware works (steppers,
          servos, drivers, etc.), then look at ways to translate design files into
          G-Code, and then decide if you want to build/buy a CNC machine.
          --
          Phil Mattison
          http://www.ohmikron.com/
          Motors::Drivers::Controllers::Software

          ----- Original Message -----
          From: scott102006 <scott102006@...>
          To: <SherlineCNC@yahoogroups.com>
          Sent: Wednesday, September 05, 2007 11:08 AM
          Subject: [SherlineCNC] Difficulty of using a CNC Mill/Lathe?


          > I don't have a CNC Mill or lathe at the moment, I was planning on
          > getting one before the end of the year but am now having second
          > thoughts. How hard is it to design parts and create g-code? I don't
          > really understand how it works at this point. Do you design the part
          > in a program and it generates the code for you, or do you write it
          > yourself? Is there any way I can make sure I am capable of designing
          > parts and generating code before I drop $3,000+ in a mill or lathe?
          >
          > Thanks for any help.
          >
          >
          >
          >
          > Yahoo! Groups Links
          >
          >
          >
        • Alan Wright
          Scott, It is not difficult to design parts using CAD software, and I guess I would rate g-code as a relatively simple type of programming. Picking either up
          Message 4 of 11 , Sep 6, 2007
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            Scott,

            It is not difficult to design parts using CAD software,
            and I guess I would rate g-code as a relatively simple
            type of programming. Picking either up depends on your
            aptitude.

            To bridge the gap between these two representations of
            a part you typically will use CAM software. This type
            of software ranges from cheap and easy to use all the
            way to incredibly expensive and complicated.

            One last alternative, depending on the types of parts
            you want to make, is to simply generate g-code without
            going through the CAD/CAM steps but also without hand
            coding. This is accomplished using "wizards" such as
            those provided with Mach3, and those of us inclined
            towards programming write a lot of these ourselves.

            The idea is to describe each operation you want to do
            on the part (such as surfacing, cutting a slot or pocket,
            drilling some holes, etc) by means of a set of parameters,
            and then either execute these one at a time or chain some
            number of these together. For whatever reason, this is how
            I like to work, since I'm just a hobbyist, and CNC is just
            a way to accelerate manual work.

            Alan


            --- In SherlineCNC@yahoogroups.com, "scott102006" <scott102006@...>
            wrote:
            >
            > I don't have a CNC Mill or lathe at the moment, I was planning on
            > getting one before the end of the year but am now having second
            > thoughts. How hard is it to design parts and create g-code? I don't
            > really understand how it works at this point. Do you design the
            part
            > in a program and it generates the code for you, or do you write it
            > yourself? Is there any way I can make sure I am capable of
            designing
            > parts and generating code before I drop $3,000+ in a mill or lathe?
            >
            > Thanks for any help.
            >
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