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chamnit

Member Since: July 8, 2011

Country: United States

  • Lol. True. But, I would also add that Haas production CNC mills and Tormach mills are mostly column mills, rather than knee mills. Each mill design lends to different applications and strengths and weaknesses. And, both are used in production for metal subtractive manufacturting.

  • No it's not technically a knee mill, but a column mill. The usage and general design are similar. I had a feeling that I would get a comment about it. If you read "Tabletop Machining" by Joe Martin, the creator of Sherline, he references the Bridgeport knee mill as the reference point for their mill design several times. I think that Sherline made the decision to make a column mill rather than a traditional knee mill design based on being more compatible with their Sherline lathe and existing parts and being less massive, as you stated.

    Either way, the Sherline mill was designed based on the miniaturization of the Bridgeport and to cut metal on the tabletop, not softer materials like woods and plastics. It can, but isn't ideally suited for it since the max feed rates are slow. It's high torque, rather than high speed.

  • I disagree. This is a different mill type (gantry) than a Sherline (knee-mill) and each are used for two different purposes. I own a Sherline 5400 that has been CNC'd. It does have a "real" headstock that is pretty good at cutting metals (not quickly though) like aluminum, brass, and steel, but it isn't built to cut wood fast or deal with the dust very well. The lead screws would gum up badly.

    These hobby gantry mills are designed for larger flat sheet stock, like foams, woods, and plastics. And can cut aluminum much faster than my Sherline, up to 3x-5x faster surprisingly. You have to use high-speed machining tool paths and carbide bits. It won't be as precise and accurate, but a gantry mill isn't used for that. It's typically for large stock jobs that is milled relatively quickly with a high RPM spindle.

    Generally, I opt for the Sherline whenever I need precision metal work or need to cut steel. These gantry routers are great for wood and cutting fast jobs, because they have a much higher max feedrate (200ipm) than my Sherline (25-30ipm). There are even videos of similar gantry-style milling machines cutting pine wood at 600ipm+ with high-speed machining tool paths and trim routers.

  • I think you're trying to compare two wholly different types of machines. Apples and oranges, so to speak.

    You can't cut metal or hardwoods with a Printrbot or any 3d printer, because they aren't built to take the mechanical loads involved with CNC routing. 3d printers only have to move a print head and the extruders never contact anything. With a CNC router, you can have inertial and cutting forces that can exceed tens of pounds. To maintain cut accuracy with those types of loads, you need more material to stiffen up the machine. You also need a base stiff enough to clamp the workpiece to so it doesn't go flying off.

    If you add up the fact that there is more material in the extrusions, a larger footprint, larger Nema23 motors, it still cheaper than a PrintrBot Simple Metal 10"x10"x10" 3d printer. I'm not sure how you can still justify your comment.

    Case and point. See YouTube videos on this machine cutting aluminum like a champ. Try doing that with a flimsy 3d printer with a 10 pound trim router hanging from the extruder head.

  • Agreed. Belts are surprisingly capable, very affordable, and don't suffer from backlash problems that lead screws often do. There are a few YouTube videos with the ShapeOko3 cutting aluminum at very fast rates. With these modern trim routers, like the Dewalt 611, you can do high-speed machining tool paths in aluminum. It's pretty amazing. That said, you probably won't get super precise cuts when cutting metal, but then again, thousandths or ten thousandth of an inch accuracy isn't what this machine is for.

  • Lead developer of Grbl here. I'm committed to fully supporting the StepOko board. You should be able to upload Grbl firmware updates via Grbl's supported Arduino IDE uploading method. I think you have to select either the Arduino Uno or Duemilanove as the board type. Not sure which yet.

No public wish lists :(