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  • "Desktop" CNC mill options?

    I've been considering getting a small, entry-level CNC mill as something to practice/train with, as I'm still pretty weak on the whole CNC model-toolpath-machine workflow.

    The two ideas I've been considering is either going as dirt-cheap as I can, probably by picking up one of the cheap eBay "rounters" like Fixerdave did a while back, or maybe investing a bit more into a semidecent machine that can cut actual aluminum parts.

    I'm still trying to save up for a "real" machine, probably a Tormach, so I'd rather not spend too much out of that budget. Let's say $1,500 or under would be ideal, with max around $3K.

    Options I've kind of glanced at so far: Carbide Create's Nomad, by the same people that make the Shapeoko routers. I'm pretty happy with the build quality and OS interface of my Shapeoko, and the Nomad is supposed to be able to do aluminum- albeit slowly, which is to be expected- right out of the box. A bit high at $2,500, but comes pretty well rated.

    LMS has their SEIG CNC mill, which is $4K out of the box. That's more than I'd like to spend right now (especially since in many cases, I'm looking at another $200 to $500 to get it shipped up here.) The mill appears well regarded, but I'd prefer not to spend that much.

    The Leading Edge machines commonly seen at the top of this page start at $5K, so they're right out.

    I know both Sherline and Taig make their little desktops in CNC or even just CNC-ready versions, but those always seemed a bit weedy to me. I think I'd prefer to go with the dirt-cheap router-only option and just cut blocks of machinists' wax. Anyone with experience with either of those?

    I've seen preconverted Grizzlies, and kits to convert them, but on the latter, I'm not looking for another project right now. If I went that route, I've already got a buddies' mini Grizzly on the table I'm heping convert, but as neither one of us have a lot of spare time, it's kind of slow going.

    PocketNC makes a cute little 5-axis, but that's $5,500, and at the moment, I have enough trouble understanding three axis, let alone five.

    Anyone have any other options or recommendations?

    Doc.
    Doc's Machine. (Probably not what you expect.)

  • #2
    http://bbs.homeshopmachinist.net/thr...highlight=taig
    *** I always wanted a welding stinger that looked like the north end of a south bound chicken. Often my welds look like somebody pointed the wrong end of a chicken at the joint and squeezed until something came out. Might as well look the part.

    Comment


    • #3
      What do you mean by “weedy”? My CNC Taig handles most everything I throw at it material-wise... 6061 and 7075 aluminum, A36, 4140PH, 6Al4V titanium, 17-4PH stainless, phenolic, Macor ceramic... When tuned up it’ll hold close tolerances and 180in/min rapids, while cutting at 100in/min. I generally use 1/8” or 1/4” endmills, but have gone as big as 10mm and 3” slitting saws.

      I’d like to see a router do that.

      Comment


      • #4
        Originally posted by adatesman View Post
        What do you mean by “weedy”? My CNC Taig handles most everything I throw at it material-wise... 6061 and 7075 aluminum, A36, 4140PH, 6Al4V titanium, 17-4PH stainless, phenolic, Macor ceramic... When tuned up it’ll hold close tolerances and 180in/min rapids, while cutting at 100in/min. I generally use 1/8” or 1/4” endmills, but have gone as big as 10mm and 3” slitting saws.

        I’d like to see a router do that.
        Ah, you must have a ball screw version. Would that I had started with something so cool. Now if they would just offer a fixed column option....
        *** I always wanted a welding stinger that looked like the north end of a south bound chicken. Often my welds look like somebody pointed the wrong end of a chicken at the joint and squeezed until something came out. Might as well look the part.

        Comment


        • #5
          Nope. 15 year old ground leadscrew option. Gecko G540, generic Xylotex steppers, KFlop driver (which made a huge difference over my former Xylotex driver, which lost steps at 80in/min rapids). Taking the time to set it up carefully is a pain, but pays dividends. I have no problem circle interperlating to +/-0.001, and hold closer than that on longitudinal moves.

          Fixing the column is a simple matter of bolting on some blocks, tramming, drilling, taper reaming, then adding a taper pin. Or bolting shelf brackets to either side of the column with adjustable bolts.

          I’ve not bothered, as I have no problems with it kicking out of tram. With CNC, multiple light passes are key to not overloading that joint, same as on a Bridgeport.
          Last edited by adatesman; 09-21-2018, 08:51 PM.

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          • #6
            Originally posted by Doc Nickel View Post
            Anyone have any other options or recommendations?
            Leave it in your cart and maybe Bob's wife will buy it for you?

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            • #7
              Originally posted by glug View Post
              leave it in your cart and maybe bob's wife will buy it for you?
              lol - irl
              *** I always wanted a welding stinger that looked like the north end of a south bound chicken. Often my welds look like somebody pointed the wrong end of a chicken at the joint and squeezed until something came out. Might as well look the part.

              Comment


              • #8
                I think a very important element of learning CNC is your CAD/CAM software. Give that some thought before buying anything. You can learn quite a lot by the design/CAM/simulate process - if your CAM package has a simulator (or you have and independent simulator). I realize this is not the cheap route, but I use Solidworks/Visual Cam for Solidworks. There are many good less expensive options. I would get the software lined up and working before buying anything.

                Comment


                • #9
                  I don't think there's that much you could learn spending $500, or even $1000, on a desktop 'mill', that you wouldn't learn within the first week of having a Tormach or similar sized machine. Plow that money into making swarf and breaking tools instead.

                  I mean, the hard part of CNC is learning how to translate your understanding of how a part should be machined into CAM strategies, and you pick it up really fast. It's certainly nothing that you couldn't learn far more effectively sitting down a few nights with Fusion360, drawing some parts you know how to make manually, then trying to replicate those toolpaths in CAM and simulating them using the built in simulator. There's a gazillion tutorials on YouTube covering exactly that.

                  The part that you really need your target machine in hand for, is wrapping your head around feeds and speeds, and how your machine and any particular tool and material combination work together - and how to translate that into cutting parameters to feed into CAM. But again, that's more of a 'sit down with your new machine, the MDI interface, some material samples, and break a few tools while you trial and error it. It's translating your manual machinist 'this is what a good cut feels and sounds like' sense into a 'these are the numbers that make a good cut' sense.

                  Comment


                  • #10
                    When you do get a machine, cut some air first. It is a good idea to do that for a while for each setup until you are confident.

                    Comment


                    • #11
                      Originally posted by adatesman View Post
                      Nope. 15 year old ground leadscrew option. Gecko G540, generic Xylotex steppers, KFlop driver (which made a huge difference over my former Xylotex driver, which lost steps at 80in/min rapids). Taking the time to set it up carefully is a pain, but pays dividends. I have no problem circle interperlating to +/-0.001, and hold closer than that on longitudinal moves.

                      Fixing the column is a simple matter of bolting on some blocks, tramming, drilling, taper reaming, then adding a taper pin. Or bolting shelf brackets to either side of the column with adjustable bolts.

                      I’ve not bothered, as I have no problems with it kicking out of tram. With CNC, multiple light passes are key to not overloading that joint, same as on a Bridgeport.
                      That's pretty amazing then. Jeff Birt (Soigeneris), who has probably built and dialed in more Taig's than anybody, was only able to get those kind of speeds by massively loosening up the machine. I spoke with John Herzog (the creator of the Taig mills) a few times as well, and he didn't say it was impossible to run it both fast and tight, but he asked in that defensive tone some folks use why you would want to. Of course we know why you would want to run it low power fast spindle machine with high feeds. Its the way the machine can be most effectively utilized.

                      I have to say you have achieved something hundreds if not thousands of Taig users only aspire to. Kudos to you. Maybe you should pop in over at the Taig Owners forum and tell us all how to do it. I bet you would have an enraptured audience.
                      *** I always wanted a welding stinger that looked like the north end of a south bound chicken. Often my welds look like somebody pointed the wrong end of a chicken at the joint and squeezed until something came out. Might as well look the part.

                      Comment


                      • #12
                        I'm with sun god. If you have your heart set on a Tormach then buy one and learn on it. Cutting out the middle cnc machine will probably save you time and money in the long run. I generally regret buying a so called learning machine because then I have to get rid of it. But mostly I tend to be dissatisfied with it knowing full well that the machine I really want could do the job much better. Just my 2 cents.

                        Just a reminder. There are 2 CNC mills available in the state. One in Fairbanks and one near Anchorage. The one near Anchorage is a new Sharp.

                        Ron

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                        • #13
                          In this case, I'm really kind of just checking my options.

                          Yes, I still want a Tormach, but at the moment, I'm holding out for the new "MX" series machines, with servos and an ISO30 spindle. And according to the company, they won't be available for at least another four to six months.

                          It'd be nice if I could spend that time learning more about mill operation, especially on something cheaper than $15K worth of Tormach if and when I crash it.

                          I like the idea of the little dirt-cheap eBay machine like Fixerdave got- it'd only really be good for balsa wood or machinists' wax, but it'd at least be something- and I could toy with it right here in the office.

                          But, I also thought that if I was going to get a cheap desktop machine, I'd ask around and see if there was one that could possibly be used to cut aluminum, which means I could eventually use it to make actual parts.

                          And what mills are you talking about? There was a 1992 HAAS up on CL, but that thing was the size of a small car. I have neither the room nor the electrical capacity to run that beast.

                          Doc.
                          Doc's Machine. (Probably not what you expect.)

                          Comment


                          • #14
                            Originally posted by Bob La Londe View Post
                            That's pretty amazing then. Jeff Birt (Soigeneris), who has probably built and dialed in more Taig's than anybody, was only able to get those kind of speeds by massively loosening up the machine. I spoke with John Herzog (the creator of the Taig mills) a few times as well, and he didn't say it was impossible to run it both fast and tight, but he asked in that defensive tone some folks use why you would want to. Of course we know why you would want to run it low power fast spindle machine with high feeds. Its the way the machine can be most effectively utilized.

                            I have to say you have achieved something hundreds if not thousands of Taig users only aspire to. Kudos to you. Maybe you should pop in over at the Taig Owners forum and tell us all how to do it. I bet you would have an enraptured audience.
                            All it took was attention to detail, good lubrication, and a lot of time spent tweaking the settings in KFlop.

                            <shrug>

                            Comment


                            • #15
                              Originally posted by Doc Nickel View Post

                              And what mills are you talking about? There was a 1992 HAAS up on CL, but that thing was the size of a small car. I have neither the room nor the electrical capacity to run that beast.

                              Doc.
                              Doc,

                              Probably best if you call me or email me if you're interested in either machine.

                              Ron

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