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  • Insert Coin: 1 Player Start!

    I have an AC Tech VFD on my Sheldon lathe, and while I love the features (easy reversing, speed control, soft start, etc.) I heavily disliked the membrane switches. They had no "feel" and weren't well placed. (I mounted the VFD box knowing, however, that I'd be adding remote buttons, so that wasn't really a fault of the box.)

    I've been doing a great deal of lathework recently, and got tired of poking at the stock controls. I first looked around for "real" machine controls- good industrial buttons that were designed for the job.

    However, most of them were $30 to $50 each and went up from there. I didn't necessarily need them to be water or oil proof (no flood coolant, lathe's indoors) and they didn't need to be rated for heavy AC current (5V signal, virtually nil amperage.)

    So I ordered a handful of big buttons designed for arcade video game cabinets.

    They ran me about $2.50 each, have a replaceable microswitch supposedly rated for ten million actuations, and they were available in a variety of colors. I got 'em in last Thursday, and spent Sunday installing them.

    The housing is a chunk of 1-3/4" x 4" aluminum box tubing, with endplates milled from a bar of 2x1/4".



    The front face is angled, and both plates are stepped to lock into the box tubing. Two 3" 10-32 screws go from the front and thread into the back to hold everything together.



    Then it simply bolts to the side of an aluminum tray that some previous owner had mounted to the top of the headstock cover (partly as a place to set tools and parts, and partly to cover a slot in the lid, that had probably been cut for an overhead style belt drive.)



    A light signal wire runs down the back and connects to the VFD. It works great, the buttons are easy to stab, have a nice solid "clicky" feel and I don't have to reach as far.

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

  • #2
    Looks good! Where did you order the buttons from?
    ----------
    Try to make a living, not a killing. -- Utah Phillips
    Don't believe everything you know. -- Bumper sticker
    Everybody is ignorant, only on different subjects. -- Will Rogers
    There are lots of people who mistake their imagination for their memory. - Josh Billings
    Law of Logical Argument - Anything is possible if you don't know what you are talking about.
    Don't own anything you have to feed or paint. - Hood River Blackie

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    • #3
      I picked these up from Quarter Arcade, but Happ Controls has a wider selection. (I went with QA simply because their "checkout" system was considerably easier and faster.)

      I got four each red and green, two blacks, and one each white and yellow. Less than $50 including shipping. I may well eventually redo the Logan lathe with a 3ph/VFD as well, as I like the speed control and soft start of the Sheldon. If I do, I'll make another box just like this, and mount it in a similar location (the Logan already has a drum switch mounted in the same relative position.)

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

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      • #4
        Thanks Doc. I may look into that. I've got some wimpy Rat Shack pushbuttons on my VFD remote that work, but they sure don't look the part.
        ----------
        Try to make a living, not a killing. -- Utah Phillips
        Don't believe everything you know. -- Bumper sticker
        Everybody is ignorant, only on different subjects. -- Will Rogers
        There are lots of people who mistake their imagination for their memory. - Josh Billings
        Law of Logical Argument - Anything is possible if you don't know what you are talking about.
        Don't own anything you have to feed or paint. - Hood River Blackie

        Comment


        • #5
          May I suggest a fairly simple modification? A guarded setup to make it easy to push "stop" and harder to push 'go".

          The usual way is to put the "go" button inside a ring or guard (or recess it), and leave the "stop" button sticking out.

          That way, you can simply slap the buttons in an emergency, and automatically have a nearly 100% chance of stopping the machine.... You don't want to have to make an accurate "push" when there is a problem.........
          1601

          Keep eye on ball.
          Hashim Khan

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          • #6
            Doc what a neat idea. I would have never thought of that.

            I also took some time to look throught your whiteboard. Had some good laughs

            J T. Good suggestion.

            Rob

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            • #7
              JT- Thought of that, but it's not necessary. The "stop" signal requires a constant connection through a normally closed switch. If that connection is broken, the motor stops. You can push both buttons simultaneously, while it's running, and it'll still stop.

              Also, I'm considering mounting a second "stop" button on the drip tray, down and to the right of the operators' usual position, giving a second option for an E-stop in case, for example, a big wad of swarf gets wrapped up in the chuck and is whipping around.

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

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              • #8
                Doc-
                Mine is similar, but I also included a reversing switch and a speed pot, in addition to start and stop. I really like being able to adjust the speed while facing. Worth a thought.

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                • #9
                  Originally posted by Doc Nickel
                  JT- Thought of that, but it's not necessary. The "stop" signal requires a constant connection through a normally closed switch. If that connection is broken, the motor stops. You can push both buttons simultaneously, while it's running, and it'll still stop.
                  Yes, it WILL stop if you press BOTH.

                  if you MISS the stop, it won't, of course.

                  And, if you LET GO of the start button LAST (after pushing both), it may re-start. That is the reason it is a standard OSHA requirement, and present on every such setup........... worth thinking about even if you HATE OSHA
                  1601

                  Keep eye on ball.
                  Hashim Khan

                  Comment


                  • #10
                    Originally posted by J Tiers
                    And, if you LET GO of the start button LAST (after pushing both), it may re-start.
                    -Yessir. As I said, I'm considering a separate E-stop button mounted away from the spindle.

                    For that matter, I've also recently considered making a sort of "electric micrometer stop". A switch that mounts to the bedway, and when the carrige hits the switch, the motor stops.

                    That'd help some on repetitive tasks like boring or long turning jobs- not so I can go do other things (as in leave the lathe) but so I could, for example, deburr the previous parts, or other minor tasks.

                    That's kind of iffy, in that it can lead to sloppy practice, so I'll need to think on it some.

                    Bruce- Both reverse and the speed adjustment are used so infrequently that having to reach over to the control box itself isn't a big deal. I'd considered trying to make a full "control panel" but I didn't really have a place to mount something that size.

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

                    Comment


                    • #11
                      Doc, I did the thing on my lathe that you are thinking of. Works well in test so far. I am using a AC Brushless servo so my performance is going to be different than yours.

                      I used a microswitch with a couple rare earth magnets glued to the side so it sticks to the ways. My drive is set up to use the drum switch built into the lathe. One common wire and one for fwd and rev. I used the switch N.C. in series with the forward lead so when the carriage hits the switch the spindle shuts down.

                      I chucked up a piece of 1-1/4" PVC in the lathe and put a fine tip sharpie in one of the toolholders. At about 600 RPM the carriage will stop usually less than .001 of the same spot at max feed. 9 times out of 10 within .0005. This translates to stopping the spindle within +/- 1/16" on the circumference of the PVC pipe. Thats about the backlash of the drive.

                      At higher speeds it takes longer for the drive to decelerate so it actually pushed the switch down the ways before it came to a stop.

                      Monarch actually has an option like this called ELSR (Electric Lead Screw Reverse) and there are cams set on a rod to stop the lathe, I think.

                      Heres a vid I took this week of my lathe drilling. At the end you can see how fast my lathe stops. A VFD wont stop this fast but you can help it by adding brake resistors if your drive supports it.

                      Comment


                      • #12
                        OSHA requires the start to be guarded and the stop to lock in the off position so that it must be manually operated to reenable the start function. Same rules here in Canada too.

                        Although you can do what you like in a home shop I decided to follow the rules when I designed my CNC controller. As you can see the main power is guarded as is the motor power. That also controls spindle power. The E-stop locks in and must be rotated to release it so that the motor power switch can be used again to enable drives. If the E-stop is locked in nothing will run until it is released even if the main power is cycled. If power fails and comes back on it starts up disabled.

                        Free software for calculating bolt circles and similar: Click Here

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                        • #13
                          I got all the components for my mill's control box from automation direct. the buttons, legend plates and pre-drilled box were all pretty cheap-less than ten bucks each. The only expensive part was the speed pot at $35. (but it came with a professional mounting and fit right into the 22mm holes in the box.



                          It's mounted with a piece of bent up angle iron which also holds my el-cheapo goose neck desk, err, work lamp.

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                          • #14
                            well done DOC a little ingenuity goes along way looking good or should I say to an engineer such as your good self engine youityAlistair best regards
                            Please excuse my typing as I have a form of parkinsons disease

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                            • #15
                              Robbie how did you do the printing?Alistair
                              Please excuse my typing as I have a form of parkinsons disease

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