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  • Spindle brake on a mill question...

    For about the past year or so, I've been rebuilding an Anayak "Exacto" vertical mill that was given to me last July.

    After some seven months' wait just on a couple of gears to be made, I've got it almost 100% back together.



    My current issue is now that I've been able to power the head, I discovered that the spindle is bent a full 15 thou out. I'll be dismantling that to see if it can be repaired in the next week or so.

    But my question is, the spindle brake mechanism was entirely gone. There's a boss for it on the side of the belt cover, that had two broken-off screws in it, but that's it. No lever, no internal mechanism, no nothing. And looking at photos of other mills of this type online, the lever pivots vertically, not horizontally as on a Bridgeport.

    Does anyone have any idea how that mechanism works? Or a suggestion for a homebrew mechanism that would work? Or better yet, can provide photos of the factory mechanism so that I can duplicate it?

    And, going along with that, if I were to fabricate my own system, what would be good to use as a friction material for the contact pad? (The pulley has a cast-iron ring attached, as the wear surface.)

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

  • #2
    Originally posted by Doc Nickel View Post
    For about the past year or so, I've been rebuilding an Anayak "Exacto" vertical mill that was given to me last July.

    After some seven months' wait just on a couple of gears to be made, I've got it almost 100% back together.



    My current issue is now that I've been able to power the head, I discovered that the spindle is bent a full 15 thou out. I'll be dismantling that to see if it can be repaired in the next week or so.

    But my question is, the spindle brake mechanism was entirely gone. There's a boss for it on the side of the belt cover, that had two broken-off screws in it, but that's it. No lever, no internal mechanism, no nothing. And looking at photos of other mills of this type online, the lever pivots vertically, not horizontally as on a Bridgeport.

    Does anyone have any idea how that mechanism works? Or a suggestion for a homebrew mechanism that would work? Or better yet, can provide photos of the factory mechanism so that I can duplicate it?

    And, going along with that, if I were to fabricate my own system, what would be good to use as a friction material for the contact pad? (The pulley has a cast-iron ring attached, as the wear surface.)

    Doc.
    I'm sure all that was in that hole was a plunger. The handle is a cam that is free to pivott to any position horizontal to vert.

    Steel strapping will serve nicely as the brake band, Line it with leather, cork or micarta. It's not going to see heat.

    Look what you can buy! ;-)
    https://www.ombwarehouse.com/mini-bi...akes-and-kits/

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    • #3
      This is snowmobile brake setup that I made for my Varnamo Mill,has worked flawless.The handbrake controll is equiped with limit switch that disconnect motor when applied works great for tapping with the spindle and as a bonus the park brake function works great for tool changes.Motor will not start if park brake is on.

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      • #4
        My Excello 602 uses a lever on a cam vs. a Bridgeport style brake lever. Nice thing about this setup is you could fully lock the cam in position to have the brake hold "hands free", just don't forget to take it off when done.

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        • #5
          You may not need a brake, it looks like you are powering the motor with a VFD (On the table?) The VFD can be programmed to stop the motor almost instantly. Absolutely spot on for tapping as it will also almost instantly reverse.

          Ian

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          • #6
            Originally posted by dvbydt View Post
            You may not need a brake, it looks like you are powering the motor with a VFD (On the table?) The VFD can be programmed to stop the motor almost instantly. Absolutely spot on for tapping as it will also almost instantly reverse.

            Ian
            How does VFD work for tooling changes.

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            • #7
              I don't know if I have seen anybody use their brake (on youtube). If it is used to hold the spindle
              so that you can tighten the collet drawbar, then i get it.

              My Millrite has a brake and a pin that locks the spindle for drawbar tightening. I have never used the
              brake. I have thought about taking it off and using the bracket for something trick.
              John Titor, when are you.

              Comment


              • #8
                [QUOTE=Mike Amick;1120683]I don't know if I have seen anybody use their brake (on youtube). If it is used to hold the spindle
                so that you can tighten the collet drawbar, then i get it.

                The brake thing makes tool changing easy when switching out collets on TG 100 tool holder or removingISO 40 taper tooling,this braking system is a lot stronger that would come on Mills from factory I would think.It designed to stop 70 lb track spinning at 80 mph to stop in a split second.
                Last edited by Tundra Twin Track; 06-10-2017, 08:40 PM.

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                • #9
                  Doc, That mill looks nice

                  My combination H/V 30NMTB mill has no brake on the Vert. spindle. I wish it did!

                  Two wrench tool changes are for the birds. ;-)

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                  • #10
                    I have a Kurt brand power draw bar (air impactor). Never needed to use the brake for tool changing. I might use it if I broach with the spindle (carefully) but never have done this.

                    The VFD brakes the spindle in a second or so for most tooling weight/speeds.
                    Last edited by lakeside53; 06-11-2017, 11:31 AM.

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                    • #11
                      Originally posted by CalM View Post
                      I'm sure all that was in that hole was a plunger. The handle is a cam that is free to pivott to any position horizontal to vert.
                      -Hum. I suppose that's an idea.

                      Steel strapping will serve nicely as the brake band[.]
                      -There's no bosses or mountings inside the pulley case for a band-style brake.

                      This is snowmobile brake setup that I made for my Varnamo Mill,has worked flawless.
                      -There's no room in there for an additional brake disc, let alone a caliper.

                      You may not need a brake, it looks like you are powering the motor with a VFD (On the table?)
                      -Temporarily, yes, just for test purposes. And yes, the VFD will slow the motor rapidly or even stop it dead, but it doesn't "lock" it like a brake. As noted, a brake is needed for tool changes- at the moment, my only other option would be a strap wrench on the spindle nose.

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

                      Comment


                      • #12
                        Originally posted by Tundra Twin Track View Post
                        This is snowmobile brake setup that I made for my Varnamo Mill,has worked flawless.The handbrake controll is equiped with limit switch that disconnect motor when applied works great for tapping with the spindle and as a bonus the park brake function works great for tool changes.Motor will not start if park brake is on.
                        that's what I had in mind, very well done
                        Ed
                        Agua Dulce, So.California
                        1950 F1 street rod
                        1949 F1 stock V8 flathead
                        1948 F6 350 chevy/rest stock, no dump bed
                        1953 chevy 3100 AD for 85 S10 frame have a 4BT cummins motor, NV4500
                        1968 Baha Bug with 2.2 ecotec motor, king coil-overs,P/S

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                        • #13
                          A bent spindle and broken screws in the brake lever system sound potentially related.......

                          Perhaps straightening as well as possible and then re grinding the spindle collet recess?
                          1601

                          Keep eye on ball.
                          Hashim Khan

                          Comment


                          • #14
                            That's what I have in mind. I'll pull the quill later this week and dismantle it, and check the spindle on a granite flat with V-blocks.

                            I suspect the "bend" is right where the bottom end flares out below the lower bearing- which is typical for a tool-into-work crash.

                            I'll try and gently bend it back as necessary, using my press and probably some hardwood saddle blocks. Assuming I can get the bulk of the bend out (as I said, it's about 15 thou) and make sure the rest of the shaft is fairly straight, I'll reassemble the quill with new bearings, which will undoubtedly cost a pretty penny.

                            Then, once it's assembled, I'll regrind the collet taper in place. I did that last year when rebuilding the mill-drill, and the results were damn near perfect.

                            On this brake, I'm thinking I'd like to have a lever that actuates the same way as the one on my Grizzly, which is a bolt-for-bolt Bridgeport clone, so the lever pushes horizontally to the rear to stop.

                            So how about this:



                            I'll strip the paint back off the housing- which is aluminum- and weld a couple of new "ears" to the front of the original brake-lever boss. Then mill a slot between the ears and the old bore, so a lever can be fitted. The lever will pivot off the new 'ears' (drilled vertical hole with a pin) and push a slug down the bore (which I might bore out slightly to make sure it's clean and smooth.) On the end of the 'piston', I'll just counterbore it back an inch or so, and press in a chunk of wood dowel as a "brake shoe". There'll need to be a return spring in there somewhere, but that could be put one of several places.

                            Then repaint and reinstall. The action will be "push horizontally to the rear" just like the Grizzly/Bridgeport, and at about the same height, so habit and muscle memory won't get confused. And it's probably easier than trying to find replacement parts for a rare-in-the-US Spanish-made machine.

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

                            Comment


                            • #15
                              Originally posted by oxford View Post
                              My Excello 602 uses a lever on a cam vs. a Bridgeport style brake lever. Nice thing about this setup is you could fully lock the cam in position to have the brake hold "hands free", just don't forget to take it off when done.
                              On the Excello's I retro-fitted to VFD, I used a two position SW for the brake, Man/Auto, for ease of using Kwik-Change collets, For safety I interlocked using a VFD output set to At-Zero-Speed, if not at this, it released the brake automatically.
                              Max.

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