7 ms·

> everything is rubber I've been saying this for years. I go one step further, I call it "resonant rubber" --a mythical material that actively conspires to ev

> everything is rubber I've been saying this for years. I go one step further, I call it "resonant rubber" --a mythical material that actively conspires to evade everything you are trying to do to it and has a mind of its own.

theelous3 5y ago
Ha! Yes, even more accurate. I just motorized my quill feed, and today's plan is to find the speed it resonates at, and program it to skip that speed band.
- robomartin 5y ago
  While we own a full machine shop at our company I still have a very, well, unique, garage. At the moment I have my old manual Bridgeport knee mill and a Haas VF2 right next to it (along with a prototype-scale SMT line and other goodies). I've been going back and forth with the idea of turning the Bridgeport into a CNC/manual hybrid. I like the idea very much, but I also love full-manual machining. I've used such a hybrid in the past, with both a motorized knee and quill. You could still disengage the quill and simply grab handles and machine manually. The control they used was the Acu-Rite Milpwr G2: https://acu-rite.com/controls-readouts/millpwr-g2/ https://acu-rite.com/controls-readouts/millpwr-g2/ It's really nice, but fairly expensive (I think about $25K by the time you are done). One of the arguments I read against converting a manual mill this way is that the ball screws create a situation where manual machining can be more difficult due to the low friction and back-drivability. A machine builder told me it would be a better idea to trade it for a Bridgeport Boss, which is actually designed as a CNC machine. Having the VF2 next to it I don't generally feel the need to make lots of parts on the knee mill. Like it or not, it makes a mess. That's why I keep thinking that the right level of automation might be to only motorize the x and y axis for quick and accurate hole location and simple machining operations and leave the quill and knee fully manual.

theelous3 5y ago

Ha! Yes, even more accurate. I just motorized my quill feed, and today's plan is to find the speed it resonates at, and program it to skip that speed band.

robomartin 5y ago
While we own a full machine shop at our company I still have a very, well, unique, garage. At the moment I have my old manual Bridgeport knee mill and a Haas VF2 right next to it (along with a prototype-scale SMT line and other goodies). I've been going back and forth with the idea of turning the Bridgeport into a CNC/manual hybrid. I like the idea very much, but I also love full-manual machining. I've used such a hybrid in the past, with both a motorized knee and quill. You could still disengage the quill and simply grab handles and machine manually. The control they used was the Acu-Rite Milpwr G2: https://acu-rite.com/controls-readouts/millpwr-g2/ https://acu-rite.com/controls-readouts/millpwr-g2/ It's really nice, but fairly expensive (I think about $25K by the time you are done). One of the arguments I read against converting a manual mill this way is that the ball screws create a situation where manual machining can be more difficult due to the low friction and back-drivability. A machine builder told me it would be a better idea to trade it for a Bridgeport Boss, which is actually designed as a CNC machine. Having the VF2 next to it I don't generally feel the need to make lots of parts on the knee mill. Like it or not, it makes a mess. That's why I keep thinking that the right level of automation might be to only motorize the x and y axis for quick and accurate hole location and simple machining operations and leave the quill and knee fully manual.