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  • Spindle brake purpose ?

    What is the purpose of the spindle brake ? Is this a desirable feature to have ? I have noticed on some mills when one presses stop, the spindle may take up to 5 to 10 seconds to come to rest. I like to think, that if I press stop, it stops.

    Love to hear what the experts think ?


  • #2
    Just like the brakes on a car the spindle brake can help in an emergency and also save time rather than just waiting for it to coast to a stop. Also just like when you change a tire/cutting tool, it will keep the axle/spindle from rotating and help make the job easier.

    On some mills, like the Bridgeport & its clones, the off switch & the brake are separate. The Lagun however, has an off switch as part of the brake allowing one to stop it in one motion making it easier & faster. BTW, this is just one of many features of the Lagun that IMHO make it superior to a BP.

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    • #3
      When the spindle speed is set to slow using the gearbox, it takes reeeally long for the spindle to stop. In these cases, you definitely need the spindle brake.

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      • #4
        Don't know about that mill but on a Bridgeport you need the manual brake to
        be able to un-screw the draw bar. And to get the spindle stopped in a reasonable
        time to change cutters if you are running at a reasonable speed.
        ???
        ...lew...

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        • #5
          Dr Stan and Lew pretty much covered it.

          Brian
          OPEN EYES, OPEN EARS, OPEN MIND

          THINK HARDER

          BETTER TO HAVE TOOLS YOU DON'T NEED THAN TO NEED TOOLS YOU DON'T HAVE

          MY NAME IS BRIAN AND I AM A TOOLOHOLIC

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          • #6
            i don't use it often running the mill, probably should, but didn't want to have to 'do a brake job' one day some use it sparingly.

            where it is handy is to lock the spindle when using an indicator in the spindle, or a shaping operations - ie V tool for graduating dials etc
            in Toronto Ontario - where are you?

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            • #7
              Depends.
              a friction brake will slow it quickly, good for tool changes, better for CNC, of course a VFD with a good braking resistor will do nearly as well (and wear less), Makes more sense when tapping and on lathes.

              a 'peg' that goes into a hole to 'lock' the spindle is only good for unscrewing drawbars and such. it is NOT good for tightening ER32/40 collet chucks as those need 100ft-lb+ of torque and the pegs are only designed for drawbar level torque.

              Personaly, I just stick my mill in low gear range and 'wack' the wrench with my hand (it has a hammer on the other end, so nice large area to avoid hurting my hand) to tighten/loosen it.
              Play Brutal Nature, Black Moons free to play highly realistic voxel sandbox game.

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              • #8
                It is a brake. Use it.
                It is not some god awful thing if you should need to go into the head and replace it...
                Are you not machinists ? Are you not comfortable with "machines" ? How they work ? How they come apart, go together...?

                I just can't understand the reluctance to use the thing ....It is downright silly.

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                • #9
                  Mine just sits like a useless ornament most of the time. I have an air draw bar and aggressive vfd braking.

                  About the only time I use it is when my air drawbar gets stuck (need to fix that!...)

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                  • #10
                    Has anyone here actually worn out a spindle brake on a Bridgeport? How soon will I need to replace mine?
                    Weston Bye - Author, The Mechatronist column, Digital Machinist magazine
                    ~Practitioner of the Electromechanical Arts~

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                    • #11
                      You might not, but some guys do expecially if the BP was in a production environment. Just like a car... some wear out the brakes every 30,000.. some get 120,0000+ (my wife).

                      I've replaced the shoes on a few, and... on two the inside of the pulley was badly worn. I had to take a skim cut (not a great idea as it changes the brake fit radius) and build up the actuator cam to get reliable braking/holding.

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                      • #12
                        I use mine all the time when power tapping.

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                        • #13
                          On the Excello I retrofitted, it is only used for tool changes when stopped, Kwik-Change300.
                          The VFD stops the spindle in around 4 secs from high RPM.
                          The brake is only enabled by an At-Zero-speed output on the VFD to prevent activation any other time.
                          Max.

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                          • #14
                            I'm very glad I have an emergency stop and brake on my lathe. I just wonder if I'll remember it's there if I ever need it.

                            I've also used the brake when threading up to a shoulder. I don't use it this way often - the screech of the brake block in the pulley wakes the house up.

                            I know what's meant about a mill slowing down really slowly, especially in low gear. Which, incidently, is when I'd want it to stop quickly, as I mainly use slow for tapping. But I run it on a vfd, and I've never bothered to up the braking actiuon, so it seems that it doesn't bother me.

                            Where I'd really like a brake is on my bench grinder, as I often brush clothing or flesh past the freewheeling grinding wheel, and that hurts.
                            Richard - SW London, UK, EU.

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                            • #15
                              The brake on my overly-worn 1960 Bridgeport needed replacement shortly after I got it in 2004. It looked original. It was about a 2 hour job to change it, but if that happens every 44 years I'm OK.

                              I have 3-phase power and don't use it for power tapping and have quick reversal, but do use it almost every other time. It makes changing tools easier (no power draw bar), and it saves waiting for a tool to stop spinning before I change a part in the vise or make a measurement.

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